YEAST STRAINS AND MODIFIED ALBUMINS

Abstract: Albumin, for example human albumin, is expressed and secreted in yeast which has been mutated to lack the yeast aspartyl protease 3 (Yap3p) or its equivalent, thereby reducing the production of a 45kD albumin fragment. A further reduction is achieved by additionally deleting the Kex2p function. Alternatively, a modified albumin is prepared which is not susceptible to Yap3p cleavage, for example human albumin which is R410A, K413Q and K414Q.

Description: YEAST STRAINS AND MODIFIED ALBUMINS Field of the invention The present invention relates to the production of recombinant human albumin (rHA) by yeast species. Background and prior art Human serum albumin (HSA) is a protein of 585 amino acids that is responsible for a significant proportion of the osmotic pressure of serum, and also functions as a carrier of endogenous and exogenous ligands. It is used clinically in the treatment of patients with severe burns, shock, or blood loss, and at present is produced commercially by extraction from human blood. The production of recombinant human albumin (rHA) in microorganisms has been disclosed in EP 330 451 and EP 361 991. In recent years yeast species have been widely used as a host organisms for the production of heterologous proteins (reviewed by Romanos et al, 1992), including rHA (Sleep et al, 1990, 1991 ; Fleer et al, 1991). Yeasts are readily amenable to genetic manipulation, can be grown to high cell density on simple media, and as eukaryotes are suitable for production of secreted as well as cytosolic proteins. When S. cerevisiae is utilised to produce rHA, the major secreted protein is mature 67kDa albumin. However, a 45kDa N-terminal fragment of rHA is also observed (Sleep et al, 1990). A similar fragment is obtained when rHA is expressed in Kluyveromyces sp. (Fleer et al, 1991) and Pichia pastoris (EP 510 693). The fragment has the same N-terminal amino acid sequence as mature rHA, but the carboxy terminus is heterogeneous and occurs between Phe 403 and Nal 409 with the most common termini being Leu 407 and Nal 409 (Geisow et al, 1991), as shown below. -Phe-Gln-Asn-Ala-Leu-Leu-Nal-Arg-Tyr-Thr-Lys-Lys-Nal-Pro-Gln- 405 410 415 The amount of fragment produced, as a percentage of total rHA secreted, varies with both the strain and the secretion leader sequence utilised, but is never reduced to zero (Sleep et al, 1990). We have also found that the amount of fragment produced in high cell density fermentation (75-100g/L cell dry weight) is approximately five times higher than in shake flask cultures. The 45kDa albumin fragment is not observed in serum-derived human serum albumin (HSA), and its presence as non-nature-identical material in the recombinant product is undesirable. The problem addressed by the present invention is to reduce the amount of the 45kDa fragment in the product. The simplest and most obvious approach would have been to have purified it away from the full length albumin, as proposed by Gist-brocades in EP 524 681 (see especially page 4, lines 17-22). However, we have chosen a different approach, namely to try to avoid its production in the first place. Sleep et al (1990) postulated that rHA fragment is produced within the cell and is not the result of extra-cellular proteolysis. These authors codon-optimised the HSA cDΝA from Glu 382 to Ser 419 but this had no effect on production of rHA fragment. They noted that a potential Kex2p processing site in the rHA amino acid sequence, Lys 413 Lys 414 , is in close proximity to the heterogeneous carboxy terminus of the fragment, but neither use of a kex2 host strain (ie a strain harbouring a mutation in the KEX2 gene such that it does not produce the Kex2p protease), nor removal of the potential cleavage site by site-directed mutagenesis of the codon for Lys 414 , resulted in reduction in the amount of the fragment. There is a vast array of yeast proteases which could, in principle, be degrading a desired protein product, including (in 5. cerevisiae) yscA, yscB, yscY, yscS, other vacuolar proteinases, yscD, yscE, yscF (equivalent to kex2p), yscα, yscIN, yscG, yscH, yscJ, yscE and kexl. Bourbonnais et al (1991) described an S. cerevisiae endoprotease activity specific for monobasic sites, an example of which (Arg 410 ) exists in this region of albumin. This activity was later found to be attributable to yeast aspartyl protease 3 (Yap3) (Bourbonnais et al, 1993), an enzyme which was originally described by Egel-Mitani et al (1990) as an endoprotease similar to Kex2p in specificity, in that it cleaved at paired basic residues. Further work suggested that Yap3p is able to cleave monobasic sites and between, and C-terminal to, pairs of basic residues, but that cleavage at both types of sites is dependent on the sequence context (Azaryan et al, 1993; Cawley et al, 1993). As already discussed, the region of the C-terminus of rHA fragment contains both a monobasic (Arg 410 ) and a dibasic site (Lys 413 Lys 414 ). However, even though a Kex2p-like proteolytic activity is present in human cells and is responsible for cleavage of the pro sequence of HSA C-terminal to a pair of arginine residues, the fragment discussed above is not known to be produced in humans. This indicates that the basic residues Arg 410 , Lys 413 and Lys 414 are not recognised by this Kex2p-like protease, in turn suggesting that this region of the molecule may not be accessible to proteases in the secretory pathway. Thus, the Yap3p protease could not have been predicted to be responsible for the production of the 45kDa fragment. In addition, Egel-Mitani et al (1990 Yeast 6, 127-137) had shown Yap3p to be similar to Kex2p in cleaving the MFα propheromone. Since removal of the Kex2p function alone does not reduce the amount of the fragment produced, there was no reason to suppose that removal of the Yap3p function would be beneficial. Indeed, Bourbonnais et al (1993) showed that yap3 strains had a decreased ability to process pro- somatostatin, and therefore taught away from using yap3 strains in the production of heterologous proteins. Summary of the invention The solution to the problem identified above is, in accordance with the invention, to avoid or at least reduce production of the fragment in the initial fermentation, rather than to remove it during purification of the albumin. We have now found that, out of the 20 or more yeast proteases which are so far known to exist, it is in fact the Yap3p protease which is largely responsible for the 45kD fragment of rHA produced in yeast. The present invention provides a method for substantially reducing the amount of a 45kDa fragment produced when rHA is secreted from yeast species. The reduction in the amount of fragment both improves recovery of rHA during the purification process, and provides a higher quality of final product. A further, and completely unexpected, benefit of using yap3 strains of yeast is that they can produce 30- 50% more rHA than strains having the Yap3p function. This benefit cannot be accounted for merely by the reduction of rHA fragment from — 15 % to 3-5% . Thus, one aspect of the present invention provides a process for preparing albumin by secretion from a yeast genetically modified to produce and secrete the albumin, comprising culturing the yeast in a culture medium such that albumin is secreted into the medium, characterised in that the yeast cells have a reduced level of yeast aspartyl protease 3 proteolytic activity. Preferably, the said proteolytic activity is an endoprotease activity specific for monobasic sites and for paired basic amino acids in a polypeptide. Suitably, the yeast is S. cerevisiae which lacks a functional YAP3 gene. However, the invention is not limited to the use of S. cerevisiae, since the problem of 45 kDa fragment production is found also in other yeast genera, for example Pichia and Kluyveromyces , which shows that they have equivalent proteases (ie Yap3p proteolytic activity); see Clerc et al (1994), page 253. We have confirmed this by hybridisation analysis to locate homologues of Yap3p in non-Saccharomyces genera. A gene is regarded as a homologue, in general, if the sequence of the translation product has greater than 50% sequence identity to Yap3p. In non-Saccharomyces genera, the Yap3p-like protease and its gene may be named differently, but this does not of course alter their essential nature. The level of fragment can be reduced still further if, as well as substantially eliminating the Yap3p proteolytic activity, the Kex2p function is also substantially eliminated even though, as mentioned above, elimination of the Kex2p function alone does not affect the level of fragment. As in the case of Yap3p, the Kex2p function is not restricted to Saccharomyces; see Gellissen et al (1992), especially the sentence bridging pages 415 and 416, showing that Pichia has a Kex2p function. The genes encoding the Kex2p equivalent activity in Kluyveromyces lactis and Yarrowia lipolytica have been cloned (Tanguy- Rougeau et al, 1988; Enderlin & Ogrydziak, 1994). A suitable means of eliminating the activity of a protease is to disrupt the host gene encoding the protease, thereby generating a non-reverting strain missing all or part of the gene for the protease (Rothstein, 1983). Alternatively, the activity can be reduced or eliminated by classical mutagenesis procedures or by the introduction of specific point mutations by the process of transplacement (Winston et al, 1983). Preferably, the activity of the enzyme is reduced to at most 50% of the wild-type level, more preferably no more than 25%, 10% or 5 % , and most preferably is undetectable. The level of Yap3p proteolytic activity may be measured by determining the production of the 45 kDa fragment, or by the I25 I-/3 h -lipoprotein assay of Azaryan et al (1993), also used by Cawley et al (1993). Kex2p proteolytic activity may similarly be measured by known assays, for example as set out in Fuller et al (1989). The albumin may be a human albumin, or a variant thereof, or albumin from any other animal. By "variants" we include insertions, deletions and substitutions, either conservative or non-conservative, where such changes do not substantially alter the oncotic, useful ligand-binding or non-immunogenic properties of albumin. In particular, we include naturally-occurring polymorphic variants of human albumin; fragments of human albumin which include the region cleaved by Yap3p, for example those fragments disclosed in EP 322 094 (namely HSA (1- n), where n is 369 to 419) which are sufficiently long to include the Yap3p- cleaved region (ie where n is 403 to 419); and fusions of albumin (or Yap3p- cleavable portions thereof) with other proteins, for example the kind disclosed in WO 90/13653. By "conservative substitutions" is intended swaps within groups such as Gly, Ala; Nal, He, Leu; Asp, Glu; Asn, Gin; Ser, Thr; Lys, Arg; and Phe, Tyr. Such variants may be made using the methods of protein engineering and site- directed mutagenesis as described below. A second aspect of the invention provides a modified albumin having at least 90% sequence identity to a naturally-occurring albumin, which naturally- occurring albumin is susceptible to cleavage with the S. cerevisiae yeast aspartyl protease 3 (Yap3p) when expressed in yeast, characterised in that the modified albumin is not susceptible to such cleavage. Preferably, the modified albumin lacks a monobasic amino acid present in the naturally-occurring albumin protein. Suitably, the said monobasic amino acid is arginine. Conveniently, the modified albumin additionally lacks a pair of basic amino acids present in the naturally-occurring albumin, especially any of Lys, Lys; Lys, Arg; Arg, Lys; or Arg, Arg. Thus, in one particular embodiment, the naturally-occurring albumin is human albumin and the modified protein lacks Arg 410 and, optionally, one or both Lys 413 Lys 414 lysines. For example, the modified albumin may be human albumin having the amino acid changes R410A, K413Q, K414Q. Equivalent modifications in bovine serum albumin include replacing the Arg 408 and/or one or both of Arg 411 Lys 412 . The person skilled in the art will be able to identify monobasic sites and pairs of basic residues in other albumins without difficulty. The numbering of the residues corresponds to the sequence of normal mature human albumin. If the albumin is a variant (for example a polymorphic form) having a net deletion or addition of residues N-terminal to the position identified, then the numbering refers to the residues of the variant albumin which are aligned with the numbered positions of normal albumin when the two sequences are so aligned as to maximise the apparent homology. A third aspect of the invention provides a polynucleotide encoding such a modified albumin. The DNA is expressed in a suitable yeast (either the DNA being for a modified albumin, or the yeast lacking the Yap3p function) to produce an albumin. Thus, the DNA encoding the albumin may be used in accordance with known techniques, appropriately modified in view of the teachings contained herein, to construct an expression vector, which is then used to transform an appropriate yeast cell for the expression and production of the albumin. The DNA encoding the albumin may be joined to a wide variety of other DNA sequences for introduction into an appropriate host. The companion DNA will depend upon the nature of the host, the manner of the introduction of the DNA into the host, and whether episomal maintenance or integration is desired. Generally, the DNA is inserted into an expression vector, such as a plasmid, in proper orientation and correct reading frame for expression. The vector is then introduced into the host through standard techniques and, generally, it will be necessary to select for transformed host cells. Host cells that have been transformed by the recombinant DNA of the invention are then cultured for a sufficient time and under appropriate conditions known to those skilled in the art in view of the teachings disclosed herein to permit the expression and secretion of the albumin, which can then be recovered, as is known. Useful yeast plasmid vectors are pRS403-406 and pRS413-416 and are generally available from Stratagene Cloning Systems, La Jolla, CA 92037, USA. Plasmids pRS403, pRS404, pRS405 and pRS406 are Yeast Integrating plasmids (YIps) and incorporate the yeast selectable markers HIS3, TRPl, LEU2 and URA3. Plasmids pRS413-416 are Yeast Centromere plasmids (YCps). Other yeast expression plasmids are disclosed in EP-A-258 067, EP- A-286 424 and EP-A-424 117. The polynucleotide coding sequences encoding the modified albumin of the invention may have additional differences to those required to produce the modified albumin. For example, different codons can be substituted which code for the same amino acid(s) as the original codons. Alternatively, the substitute codons may code for a different amino acid that will not affect the activity or immunogenicity of the albumin or which may improve its activity or immunogenicity, as well as reducing its susceptibility to a Yap3p protease activity. For example, site-directed mutagenesis or other techniques can be employed to create single or multiple mutations, such as replacements, insertions, deletions, and transpositions, as described in Botstein and Shortle (1985). Since such modified coding sequences can be obtained by the application of known techniques to the teachings contained herein, such modified coding sequences are within the scope of the claimed invention. Exemplary genera of yeast contemplated to be useful in the practice of the present invention are Pichia, Saccharomyces, Kluyveromyces, Candida, Torulopsis, Hansenula (now reclassified as Pichia), Histoplasma, Schizosaccharomyces, Citeromyces, Pachysolen, Debaromyces, Metschunikowia, Rhodosporidium, Leucosporidium, Botryoascus, Sporidiobolus, Endomycopsis, and the like. Preferred genera are those selected from the group consisting of Pichia, Saccharomyces, Kluyveromyces, Yarrowia and Hansenula. Examples of Saccharomyces sp. are S. cerevisiae, S. italicus and S. rouxii. Examples of ' Kluyveromyces sp. are K fragilis and K. lactis. Examples of Hansenula (Pichia) sp. are H. polymorpha (now Pichia angusta), H. anomala (now P. anomala) and P. pastoris. Y. lipolytica is an example of a suitable Yarrowia species. Methods for the transformation of S. cerevisiae are taught generally in EP 251 744, EP 258 067 and WO 90/01063, all of which are incorporated herein by reference. Suitable promoters for S. cerevisiae include those associated with the PGKl gene, GALl or GALIO genes, CYCl, PH05, TRPl, ADHl, ADH2, the genes for glyceraldehyde-3-phosphate dehydrogenase, hexokinase, pyruvate decarboxylase, phosphofructokinase, triose phosphate isomerase, phosphoglucose isomerase, glucokinase, α-mating factor pheromone, a-mating factor pheromone, the PRB1 promoter, the GPD1 promoter, and hybrid promoters involving hybrids of parts of 5' regulatory regions with parts of 5' regulatory regions of other promoters or with upstream activation sites (eg the promoter of EP-A-258 067). Convenient regulatable promoters for use in Schizosaccharomyces pombe are the thiamine-repressible promoter from the nmt gene as described by Maundrell (1990) and the glucose-repressible 2» ?7 gene promoter as described by Hoffman & Winston (1990). Methods of transforming Pichia for expression of foreign genes are taught in, for example, Cregg et al (1993), and various Phillips patents (eg US 4 857 467, incorporated herein by reference), and Pichia expression kits are commercially available from Invitrogen BN, Leek, Netherlands, and Invitrogen Corp., San Diego, California. Suitable promoters include AOX1 and AOX2. The Gellissen et al (1992) paper mentioned above and Gleeson et al (1986) J. Gen. Microbiol. 132, 3459-3465 include information on Hansenula vectors and transformation, suitable promoters being MOX1 and FMD1; whilst EP 361 991, Fleer et al (1991) and other publications from Rhόne-Poulenc Rorer teach how to express foreign proteins in Kluyveromyces spp., a suitable promoter being PGKl. The transcription termination signal is preferably the 3' flanking sequence of a eukaryotic gene which contains proper signals for transcription termination and polyadenylation. Suitable 3' flanking sequences may, for example, be those of the gene naturally linked to the expression control sequence used, ie may correspond to the promoter. Alternatively, they may be different in which case the termination signal of the S. cerevisiae ADHl gene is preferred. The albumin is initially expressed with a secretion leader sequence, which may be any leader effective in the yeast chosen. Leaders useful in S. cerevisiae include that from the mating factor o- polypeptide (MFc--l) and the hybrid leaders of EP-A-387 319. Such leaders (or signals) are cleaved by the yeast before the mature albumin is released into the surrounding medium. When the yeast strain lacks Kex2p activity (or equivalent) as well as being yap3, it may be advantageous to choose a secretion leader which need not be cleaved from the albumin by Kex2p. Such leaders include those of S. cerevisiae invertase (SUC2) disclosed in JP 62-096086 (granted as 91/036516), acid phosphatase (PH05), the pre-sequence of MFα-1 , -glucanase (BGL2) and killer toxin; S. diastaticus g\uco&my\as& II; S. carlsbergensis ct-galactosϊdase (MEL1); K. lactis killer toxin; and Candida glucoamylase. Various non-limiting embodiments of the invention will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 is a general scheme for the construction of mutated rHA expression plasmids, in which HA is a human albumin coding sequence, L is a sequence encoding a secretion leader, P is the PRB1 promoter, T is the ADHl terminator, amp is an ampicillin resistance gene and LEU2 is the leucine selectable marker; Figure 2 is a drawing representing a Western blot analysis of mutant rHA secreted by S. cerevisiae, in which Track A represents the culture supernatant from DB1 cir° pAYE316 (normal rHA), Track B represents the culture supernatant from DB1 cir + pAYE464 (alteration 1), and Track C represents the culture supernatant from DB1 cir + pAYE468 (alteration 3); Figure 3 is a scheme of the construction of pAYE515; Figure 4 is a comparison of rHA fragment production by wild-type and protease-disrupted strains, presented as a drawing of an anti-HSA Western blot of culture supernatant from shake flask cultures separated by non-reducing 10% SDS/PAGE, in which Track A corresponds to DBl cir° ρAYE316, Track B corresponds to DXY10 cir° pAYE316 (yap3 strain), and Track C corresponds to ABB50 cir° pAYE316 (yap3, kex2 strain); Figure 5 is similar to Figure 4 but shows Coomassie Brilliant Blue stained 12.5 % SDS Phastgel (Pharmacia) of culture supernatants from fed batch fermentations, namely Track D for the HSA standard, Track E for DBl cir° pAYE316, Track F for DBl Akex2 cir° pAYE522, and Track G for DXY10 cir° pAYE522; and Figure 6 is a scheme for the construction of pAYE519. Detailed description of the invention All standard recombinant DNA procedures are as described in Sambrook et al (1989) unless otherwise stated. The DNA sequences encoding HSA are derived from the cDNA disclosed in EP 201 239. Example 1: Modification of the HSA cDNA. In order to investigate the role of endoproteases in the generation of rHA fragment, the HSA cDNA (SEQ1 (which includes a sequence encoding the artificial secretion leader sequence of WO 90/01063)) was modified by site- directed mutagenesis. Three separate changes were made to the HSA sequence (SEQ2). The first, using the mutagenic primer FOG1 , changed the Arg 410 codon only, replacing it with an Ala codon, leaving intact the dibasic site, Lys 413 Lys 414 . The second change, using primer FOG2, changed the residues 407-409, including the C-terminal residues of fragment, from LeuLeuNal to AlaNalAla. The third change, using the primer FOG3, altered residues 410- 414 from ArgTyrThrLysLys (SEQ3) to AlaTyrThrGlnGln (SEQ4). The oligonucleotides encoded not only the amino acid changes, but also conservative base changes that create either a Pvull or an Spel restriction site in the mutants to facilitate detection of the changed sequences. Single-stranded DNA of an M13mpl9 clone, mpl9.7 (EP 201 239; Figure 2), containing the HSA cDNA was used as the template for the mutagenesis reactions using the In Vitro Mutagenesis System, Version 2 (Amersham International pic) according to the manufacturer's instructions. Individual plaques were selected and sequenced to confirm the presence of the mutations. Double stranded RF DNA was then made from clones with the expected changes and the DNA bearing the mutation was excised on an Xbal/Sacl fragment (Figure 1). This was used to replace the corresponding wild-type fragment of pAYE309 (EP 431 880; Figure 2). The presence of the mutated Xbal/Sacl fragment within the plasmid was checked by digesting with Pvuϊl or Spel as appropriate. These Hindϊϊl fragments were excised and inserted into the expression vector pAYE219 (Figure 1) to generate the plasmids pAYE464 (alteration 1 , R410A), pAYE470 (alteration 2, L407A, L408N, N409A) and pAYE468 (alteration 3, R410A, K413Q, K414Q). These expression plasmids comprise the S. cerevisiae PRBl promoter (WO 91/02057) driving expression of the HSA/MFαl leader sequence (WO 90/01063) fused in-frame with the mutated HA coding sequence which is followed by the ADHl transcription terminator. The plasmids also contain part of the 2μm plasmid to provide replication functions and the LEU2 gene for selection of transformants. pAYE464, pAYE470 and ρAYE468 were introduced into S. cerevisiae DBl cir + (a, leu2; Sleep et al, 1990) by transformation and individual transformants were grown for 3 days at 30°C in 10ml YEPS (1 % w /v yeast extract, 2% w /v peptone, 2% /v sucrose) and then the supernatants were examined by anti-HSA Western blot for the presence of the rHA fragment. The Western blots clearly showed that fragment was still produced by the strains harbouring pAYE464, although the level was reduced slightly compared to the control expressing wild-type rHA. The mutations in the plasmid pAYE470 appeared to have no effect on the generation of fragment. However, DBl cir + pAYE468 showed a novel pattern of HSA-related bands, with little or no fragment. One example of each of DBl cir + pAYE464 and DBl cir + pAYE468 were grown to high cell density by fed batch culture in minimal medium in a fermenter (Collins, 1990). Briefly, a fermenter of 10L working volume was filled to 5L with an initial batch medium containing 50 mL/L of a concentrated salts mixture (Table 1), 10 mL/L of a trace elements solution (Table 2), 50 mL/L of a vitamins mixture (Table 3) and 20 g/L sucrose. An equal volume of feed medium containing 100 mL/L of the salts mixture, 20 mL/L of the trace elements mixture, 100 mL/L of vitamins solution and 500 g/L sucrose was held in a separate reservoir connected to the fermenter by a metering pump. The pH was maintained at 5.7 ± 0.2 by the automatic addition of ammonium hydroxide or sulphuric acid, and the temperature was maintained at 30° C. The stirrer speed was adjusted to give a dissolved oxygen tension of > 20% air saturation at 1 v/v/min air flow rate. Table 1. Salts Mixture Chemical Concentration (g/L) KH 2 P0 4 114.0 MgS0 4 12.0 CaCl 2 .6H 2 0 3.0 Na 2 EDTA 2.0 Table 2. Trace Elements Solution Chemical Concentration (g/L) ZnS0 4 .7H,0 3.0 FeS0 4 .7H 2 0 10.0 MnS0 4 .4H 2 0 3.2 CuS0 4 .5H 2 0 0.079 H 3 B0 3 1.5 KI 0.2 Na 2 Mo0 4 .2H 2 0 0.5 CoCl 2 .6H 2 0 0.56 H 3 P0 4 75mL/L Table 3. Vitamins Solution Chemical Concentration (g/L) Ca pantothenate 1.6 Nicotinic acid 1.2 m inositol 12.8 Thiamine HC1 0.32 Pyridoxine HC1 0.8 Biotin 0.008 The fermenter was inoculated with 100 mL of an overnight culture of S. cerevisiae grown in buffered minimal medium (Yeast nitrogen base [without amino acids, without ammonium sulphate, Difco] 1.7 g/L, (NH 4 ) 2 S0 4 5 g/L, citric acid monohydrate 6.09 g/L, Na 2 HP0 4 20.16 g/L, sucrose 20 g/L, pH6.5). The initial batch fermentation proceeded until the carbon source had been consumed, at which point the metering pump was switched on and the addition of feed was computer controlled (the micro MFCS system, B. Braun, Melsungen, Germany) using an algorithm based on that developed by Wang et al (1979). A mass spectrometer was used in conjunction with the computer control system to monitor the off gases from the fermentation and to control the addition of feed to maintain a set growth rate (eg 0.1 h "1 ). Maximum conversion of carbon substrate into biomass is achieved by maintaining the respiratory coefficient below 1.2 (Collins, 1990) and, by this means, cell densities of approximately 100 g/L cell dry weight can be achieved. The culture supernatants were compared with those of a wild-type rHA producer by Coomassie-stained SDS/PAGE and by Western blot. These indicated (Figure 2) that, whilst elimination of the monobasic Arg 410 (pAYE464) did reduce the level of the fragment by a useful amount, removal of both potential protease sites (pAYE468) almost abolished the 45kDa fragment. The above data suggested that the generation of rHA fragment might be due to endoproteolytic attack, though the absence of an effect of removal of the potential Kex2p site Lys 413 Lys 414 (Sleep et al, 1990, and confirmed by other studies not noted here) unless combined with elimination of Arg 410 , had suggested a complex etiology. The reduction in the amount of fragment with the mutated rHA could in principle be due to an effect of the changes on the kinetics of folding of the molecule and not due to the removal of protease cleavage sites. Example 2: Disruption of the YAP3 gene. The YAP3 gene encoding yeast aspartyl protease 3 was mutated by the process of gene disruption (Rothstein 1983) which effectively deleted part of the YAP3 coding sequence, thereby preventing the production of active Yap3p. Four oligonucleotides suitable for PCR amplification of the 5' and 3' ends of the YAP 3 gene (Egel-Mitani et al, 1990) were synthesised using an Applied Biosystems 380B Oligonucleotide Synthesiser. To assist the reader, we include as SEQ 15 the sequence of the YAP3 gene, of which 541-2250 is the coding sequence. 5' end YAP3 A : 5 ' -CGTCAGACCTTGCATGCAGCCAAGACACCCTCACATAGC-3 ' ( SEQ5 ) YAP3B : 5 ' -CCGTTACGTTCTGTGGTGGCATGCCCACTTCCAAGTCCACCG-3 ' (SEQ6 ) 3' end YAP3C: 5'-GCGTCTCATAGTGGAAAAGCTTCTAAATACGACAACTTCCCC-3' (SEQ7) YAP3D: 5'-CCCAAAATGGTACCTGTGTCATCACTCGTTGGGATAATACC-3' (SEQ8) PCR reactions were carried out to amplify individually the 5' and 3' ends of the YAP3 gene from S. cerevisiae genomic DNA (Clontech Laboratories, Inc). Conditions were as follows: 2.5μg/ml genomic DNA, 5μg/ml of each primer, denature at 94°C 61 seconds, anneal at 37°C 121 sees, extend at 72°C 181 sees for 40 cycles, followed by a 4°C soak, using a Perkin-Elmer-Cetus Thermal Cycler and a Perkin-Elmer-Cetus PCR kit according to the manufacturer's recommendations. Products were analysed by gel electrophoresis and were found to be of the expected size. The 5' fragment was digested with Sphl and cloned into the Sphl site of pUC19HX (pUC19 lacking a H dIII site) to give pAYE511 (Figure 3), in which the orientation is such that YAP 3 would be transcribed towards the Kpnl site of the pUC19ΗX polylinker. The 3' YAP3 fragment was digested with Hinάlll and Asp! IS (an isoschizomer of Kpnl) and ligated into pUC19 digested with H dIII/-4.s/?718 to give pAYE512. Plasmid DNA sequencing was carried out on the inserts to confirm that the desired sequences had been cloned. The H /2dIII/- sp718 fragment of pAYE512 was then subcloned into the corresponding sites of pAYE511 to give pAYE513 (Fig 3), in which the 5' and 3' regions of YAP3 are correctly orientated with a unique H dIII site between them. The URA3 gene was isolated from YEp24 (Botstein et al, 1979) as a HmdIII fragment and then inserted into this site to give pAYE515 (Fig 3), with URA3 flanked by the 5' and 3' regions of YAP3, and transcribed in the opposite direction to YAP3. A ura3 derivative of strain DBl cir° pAYE316 (Sleep et al, 1991) was obtained by random chemical mutagenesis and selection for resistance to 5- fluoro-orotic acid (Boeke et al, 1987). The strain was grown overnight in 100 mL buffered minimal medium and the cells were collected by centrifugation and then washed once with sterile water. The cells were then resuspended in 10 mL sterile water and 2 mL aliquots were placed in separate 15 mL Falcon tubes. A 5 mg/mL solution of N-methyl-N'-nitro-N-nitrosoguanidine (NTG) was then added to the tubes as follows: 0 μL, 20 μL, 40 μL, 80 μL or 160 μL. The cells were then incubated at 30°C for 30 min and then centrifuged and washed three times with sterile water. Finally, the cells were resuspended in 1 mL YEP (1 % w/v yeast extract, 2% w/v Bacto peptone) and stored at 4°C. The percentage of cells that survived the mutagenic treatment was determined by spreading dilutions of the samples on YEP plates containing 2% w/v sucrose and incubating at 30°C for 3 days. Cells from the treatment which gave approximately 50% survival were grown on YEP plates containing 2% w/v sucrose and then replica-plated onto YNB minimal medium containing 2% w/v sucrose and supplemented with 5-fluoro-orotic acid (1 mg/mL) and uracil (50 μg/mL). Colonies able to grow on this medium were purified, tested to verify that they were unable to grow in the absence of uracil supplementation and that this defect could be corrected by introduction of the URA3 gene by transformation. One such strain, DBU3 cir° pAYE316, was transformed with the Sphl/AspllS YAP3-URA3-YAP3 fragment of pAYE515 with selection for Ura + colonies. A Southern blot of digested genomic DNA of a number of transformants was probed with the 5' and 3' ends of the YAP3 gene and confirmed the disruption of the YAP3 gene. An anti-ΗSA Western blot of YEPS shake-flask supernatants of two transformants indicated that disruption of YAP 3 markedly reduced rHA fragment levels. One yap3 derivative of DBU3 cir° pAYE316, designated DXY10 cir° pAYE316, was grown several times by fed-batch fermentation in minimal medium to high cell dry weight. When supernatants were examined by Coomassie-stained PAGE and anti-HSA Western blot (Figs 4 and 5), the reduction in the level of rHA 45kDa fragment was clearly apparent; estimates of the amount of the degradation product vary from 7 3 to V 5 of the levels seen with the YAP3 parent. The amount of rHA produced was not adversely affected by the yap3 mutation, indeed DXY10 cir° pAYE316 was found to produce 30-50% more rHA than the YAP3 equivalent, DBl cir° pAYE316. Despite the fact that cleavage of the leader sequence from the HA sequence is C-terminal to a pair of basic residues, the rHA was found to have the correct N-terminus. The fermentation broth was centrifuged to remove the cells and then subject to affinity chromatographic purification as follows. The culture supernatant was passed through a Cibacron Blue F3GA Sepharose column (Pharmacia) which was then washed with 0.1M phosphate glycine buffer, pH8.0. The rHA was then eluted from the column with 2M NaCl, 0.1M phosphate glycine, pH8.0, at which point it was > 95% pure. It may be purified further by techniques known in the art. The albumin may alternatively be purified from the culture medium by any of the variety of known techniques for purifying albumin from serum or fermentation culture medium, for example those disclosed in WO 92/04367, Maurel et al (1989), Curling (1980) and EP 524 681. Example 3: Disruption of the KEX2 gene in a yap3 strain. To construct a strain lacking both Yap3p and Kex2p activity, a lys2 derivative of yeast strain DXY10 cir° (pAYE316) was obtained by random chemical mutagenesis and selection for resistance to o--amino adipate (Barnes and Thorner, 1985). Cells were mutagenised as in Example 2 and then plated on YNB minimal medium containing 2% w/v sucrose and supplemented with 2 mg/mL DL-α-amino adipate as the sole nitrogen source and 30 μg/mL lysine. Colonies able to grow on this medium were purified and tested to verify that they were unable to grow in the absence of lysine supplementation and that this defect could be corrected by the introduction of the LYS2 gene by transformation. This strain was then mutated by the process of gene disruption which effectively disrupted part of the KEX2 coding sequence, thereby preventing production of active Kex2p. To assist the reader, the sequence of the KEX2 gene is reproduced herein as SEQ14, of which 1329-3773 is the coding sequence. Four oligonucleotides suitable for PCR amplification of the 5' and 3' ends of the KEX2 gene (Fuller et al, 1989) were synthesised using an Applied Biosystems 380B Oligonucleotide Synthesiser. 5' end KEX2A: 5'-CCATCTGGATCCAATGGTGCTTTGGCCAAATAAATAGTTTCAGC-3' (SEQ9) KEX2B: 5'-GCTTCTTTTACCGGTAACAAGCTTGAGTCCATTGG-3' (SEQ10 3' end KEX2C: 5'-GGTAAGGTTTAGTCGACCTATTTTTTGTTTTGTCTGC-3' (SEQ11) KEX2D: 5'-GGAAACGTATGAATTCGATATCATTGATACAGACTCTGAGTACG-3' (SEQ12) PCR reactions were carried out to amplify individually the 5' and 3' ends of the KEX2 gene from S. cerevisiae genomic DNA (Clontech Laboratories Inc). Conditions were as follows: 2.5 μg/ml genomic DNA, 5 μg/ml of each primer, denature 94°C 61s, anneal 37°C 121s, extend 72°C 181s for 40 cycles, followed by a 4°C soak, using a Perkin-Elmer-Cetus Thermal Cycler and a Perkin-Elmer-Cetus PCR kit according to the manufacturer's recommendations. Products were analysed by gel electrophoresis and were found to be of the expected size (0.9 kb for the 5' product and 0.62 kb for the 3' product). The 5' product was digested with BamRl and H dIII and the 3' product was digested with HmdIII and Sail and then the two fragments were together cloned into pUC19ΗX digested with BamΑl and Sail. A 4.8 kb Hz ' ndlll fragment comprising the S. cerevisiae LYS2 gene (Barnes & Thorner, 1985) was then inserted into the resulting plasmid at H dIII (ie between the two KEX2 fragments) to form pAYE519 (Fig 6). The lys2 derivative of DXY10 cir° (pAYE316), lys2-16, was transformed with the 6.0 kb KEX2-LYS2-KEX2 fragment of pAYE519, selecting for Lys + colonies. A Southern blot of digested genomic DNA of a number of transformants was probed with the 5' and 3' ends of the KEX2 gene and confirmed the disruption of the KEX2 gene. An anti-ΗSA Western blot of YEPS shake-flask culture supernatants of these transformants indicated that disruption of KEX2 in a yap3 strain reduced the level of rΗA fragment still further, despite the lack of an effect of disruption of KEX2 alone in Example 4 below. Analysis of the rΗA produced by one such strain, ABB50, indicated that the leader sequence was incorrectly processed, leading to an abnormal N- terminus. The strain ABB50 (pAYE316) was cured of its plasmid (Sleep et αl, 1991) and transformed with a similar plasmid, pAYE522, in which the hybrid leader sequence was replaced by the S. cerevisiae invertase (SUC2) leader sequence such that the encoded leader and the junction with the HSA sequence were as follows: MLLQAFLFLLAGFAAKISA 4 DAHKS (SEQ13) Invertase leader HSA In this construct, cleavage of the leader sequence from HSA does not rely upon activity of the Kex2 protease. The strain ABB50 (pAYE522) was found to produce rHA with a similarly very low level of rHA fragment, but in this instance the N-terminus corresponded to that of serum-derived HSA, ie there was efficient and precise removal of the leader sequence. Example 4: Disruption of the KEX2 gene alone (Comparative Example). By a similar method to that disclosed in Example 3 the KEX2 gene was disrupted in S. cerevisiae. This strain had the Yap3p proteolytic activity and was therefore not within the scope of the invention. When this strain was grown in fed batch fermentation the rHA produced contained similar amounts of fragment to that produced by strains with an intact KEX2 gene. In addition, the overall level of rHA was reduced and the leader sequence was not correctly processed, leading to an abnormal N-terminus. Example 5: Identification of equivalent protease in Pichia. As noted above, non-Saccharomyces yeast similarly produce the undesirable fragment of rHA and therefore have the Yap3p proteolytic activity. We have confirmed this by performing Southern hybridisations oi Pichia angusta DNA, using the S. cerevisiae YAP3 gene as a probe. A specific DNA fragment was identified, showing that, not only is the Yap3p proteolytic activity present in P. angusta, but a specific homologue of the YAP3 gene is present also. The method of Southern hybridization used for detection of the YAP3 homologue can be adapted to clone the gene sequence from a genomic DNA library of Pichia DNA using standard procedures (Sambrook et al, 1989). Disruption of the YAP3 homologue in Pichia sp. can be achieved using similar techniques to those used above for Saccharomyces (Cregg and Madden, 1987). References (all incorporated by reference) Azaryan, A.V. et al (1993) J. Biol. Chem. 268, 11968-11975. Barnes, D.A. and Thorner, J. (1985) In Gene Manipulations in Fungi (Bennett, J.W. and Lasure, L.L., eds), pp. 197-226, Academic Press. Boeke, J.D. et al (1987) Methods Enzymol. 154, 164-175. Botstein, D. et al (1979) Gene 8, 17-24. Botstein & Shortle (1985) Science 229, 193-210. Bourbonnais, Y. et al (1991) J. Biol. Chem. 266, 13203-13209. Bourbonnais, Y. et al (1993) EMBO J. 12, 285-294. Cawley, N.X. et al (1993) FEBS Lett. 332, 273-276. Clerc et al (1994) J. Chromat. B. 662, 245-259. Collins, S.H. (1990) In Protein Production by Biotechnology (Harris, T.J.R., ed) pp. 61-77, Elsevier Science Publishers, Barking, Essex. Cregg, J.M. and Madden, K.R. (1987) In Biological Research on Industrial Yeasts, Vol. II, Stewart, G.G., Russell, I., Klein, R.D. and Hiebsch, R.R. (Eds) CRC Press, Boca Raton, FL. Cregg et al (1993) Bio /Technology 11, 905-910. Curling (1980) "Albumin Purification by Ion Exchange Chromatography", in "Methods of Plasma Protein Purification", Ed. Curling, J.M., Academic Press, London. Enderlin, CS. & Ogrydziak, D.M. (1994) Yeast 10, 67-79. Fleer, R. et al (1991) Bio /Technology 9, 968-975. Fuller, R.S. et al (1989) Proc. Natl. Acad. Sci. USA 86, 1434-1438. Geisow, M.J. et al (1991) In Techniques in Protein Chemistry II, pp. 567-572, Academic Press, Inc. Gellissen et al (1992) Tibtech 10, 413-417. Hoffmann & Winston (1990) Genetics 124, 807-816. Maundrell (1990) J. Biol. Chem. 265, 10857-10864. Maurel et al (1989) "Biotechnology of Plasma Proteins", Collogue INSERM 175, 19-24. Romanos, M.A. (1992) Yeast 8, 423-488. • Rothstein, RJ. (1983) Methods Enzymol. 101, 203-211. Sambrook, J. et al (1989) Molecular Cloning: a Laboratory Manual, 2nd edition. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY. Sleep, D. et al (1990) Bio/Technology 8, 42-46. Sleep, D. et al (1991) Bio/Technology 9, 183-187. Tanguy-Rougeau, C. et al (1988) FEBS Lett. 234, 464-470 Wang, H.Y. et al (1979) Biotech, <£ Bioeng. 21, 975. Winston, F. et al (1983) Methods Enzymol. 101, 211-228. SEQUENCE LISTING (1) GENERAL INFORMATION: (i) APPLICANT: (A) NAME: Delta Biotechnology Limited (B) STREET: Castle Court, Castle Boulevard (C) CITY: Nottingham (D) STATE: Nottinghamshire (E) COUNTRY: United Kingdom (F) POSTAL CODE (ZIP): NG7 1FD (ii) TITLE OF INVENTION: Yeast strains and modified albumins (iii) NUMBER OF SEQUENCES: 15 (iv) COMPUTER READABLE FORM: (A) MEDIUM TYPE: Floppy disk (B) COMPUTER: IBM PC compatible (C) OPERATING SYSTEM: PC-DOS/MS-DOS (D) SOFTWARE: Patentln Release #1.0, Version #1.25 (EPO) (2) INFORMATION FOR SEQ ID NO: 1: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 1830 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: CDNA to mRNA (iii) HYPOTHETICAL: NO (iii) ANTI-SENSE: NO (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapiens (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 73..1827 (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 1: ATGAAGTGGG TAAGCTTTAT TTCCCTTCTT TTTCTCTTTA GCTCGGCTTA TTCCAGGAGC 60 TTGGATAAAA GA GAT GCA CAC AAG AGT GAG GTT GCT CAT CGG TTT AAA 108 Asp Ala His Lys Ser Glu Val Ala His Arg Phe Lys 1 5 10 GAT TTG GGA GAA GAA AAT TTC AAA GCC TTG GTG TTG ATT GCC TTT GCT 156 Asp Leu Gly Glu Glu Asn Phe Lys Ala Leu Val Leu lie Ala Phe Ala 15 20 25 CAG TAT CTT CAG CAG TGT CCA TTT GAA GAT CAT GTA AAA TTA GTG AAT 204 Gin Tyr Leu Gin Gin Cys Pro Phe Glu Asp His Val Lys Leu Val Asn 30 35 40 GAA GTA ACT GAA TTT GCA AAA ACA TGT GTT GCT GAT GAG TCA GCT GAA 252 Glu Val Thr Glu Phe Ala Lys Thr Cys Val Ala Asp Glu Ser Ala Glu 45 50 55 60 AAT TGT GAC AAA TCA CTT -CAT ACC CTT TTT GGA GAC AAA TTA TGC ACA 300 Asn Cys Asp Lys Ser Leu His Thr Leu Phe Gly Asp Lys Leu Cys Thr 65 70 75 GTT GCA ACT CTT CGT GAA ACC TAT GGT GAA ATG GCT GAC TGC TGT GCA 348 Val Ala Thr Leu Arg Glu Thr Tyr Gly Glu Met Ala Asp Cys Cys Ala 80 85 90 AAA CAA GAA CCT GAG AGA AAT GAA TGC TTC TTG CAA CAC AAA GAT GAC 396 Lys Gin Glu Pro Glu Arg Asn Glu Cys Phe Leu Gin His Lys Asp Asp 95 100 105 AAC CCA AAC CTC CCC CGA TTG GTG AGA CCA GAG GTT GAT GTG ATG TGC 444 Asn Pro Asn Leu Pro Arg Leu Val Arg Pro Glu Val Asp Val Met Cys 110 115 120 ACT GCT TTT CAT GAC AAT GAA GAG ACA TTT TTG AAA AAA TAC TTA TAT 492 Thr Ala Phe His Asp Asn Glu Glu Thr Phe Leu Lys Lys Tyr Leu Tyr 125 130 135 140 GAA ATT GCC AGA AGA CAT CCT TAC TTT TAT GCC CCG GAA CTC CTT TTC 540 Glu lie Ala Arg Arg His Pro Tyr Phe Tyr Ala Pro Glu Leu Leu Phe 145 150 155 TTT GCT AAA AGG TAT AAA GCT GCT TTT ACA GAA TGT TGC CAA GCT GCT 588 Phe Ala Lys Arg Tyr Lys Ala Ala Phe Thr Glu Cys Cys Gin Ala Ala 160 165 170 GAT AAA GCT GCC TGC CTG TTG CCA AAG CTC GAT GAA CTT CGG GAT GAA 636 Asp Lys Ala Ala Cys Leu Leu Pro Lys Leu Asp Glu Leu Arg Asp Glu 175 180 185 GGG AAG GCT TCG TCT GCC AAA CAG AGA CTC AAG TGT GCC AGT CTC CAA 684 Gly Lys Ala Ser Ser Ala Lys Gin Arg Leu Lys Cys Ala Ser Leu Gin 190 195 200 AAA TTT GGA GAA AGA GCT TTC AAA GCA TGG GCA GTA GCT CGC CTG AGC 732 Lys Phe Gly Glu Arg Ala Phe Lys Ala Trp Ala Val Ala Arg Leu Ser 205 210 215 220 CAG AGA TTT CCC AAA GCT GAG TTT GCA GAA GTT TCC AAG TTA GTG ACA 780 Gin Arg Phe Pro Lys Ala Glu Phe Ala Glu Val Ser Lys Leu Val Thr 225 230 235 GAT CTT ACC AAA GTC CAC ACG GAA TGC TGC CAT GGA GAT CTG CTT GAA 828 Asp Leu Thr Lys Val His Thr Glu Cys Cys His Gly Asp Leu Leu Glu 240 245 250 TGT GCT GAT GAC AGG GCG GAC CTT GCC AAG TAT ATC TGT GAA AAT CAA 876 Cys Ala Asp Asp Arg Ala Asp Leu Ala Lys Tyr lie Cys Glu Asn Gin 255 260 265 GAT TCG ATC TCC AGT AAA CTG AAG GAA TGC TGT GAA AAA CCT CTG TTG 924 Asp Ser lie Ser Ser Lys Leu Lys Glu Cys Cys Glu Lys Pro Leu Leu 270 275 280 GAA AAA TCC CAC TGC ATT GCC GAA GTG GAA AAT GAT GAG ATG CCT GCT 972 Glu Lys Ser His Cys lie Ala Glu Val Glu Asn Asp Glu Met Pro Ala 285 290 295 300 GAC TTG CCT TCA TTA GCT GCT GAT TTT GTT GAA AGT AAG GAT GTT TGC 1020 Asp Leu Pro Ser Leu Ala Ala Asp Phe Val Glu Ser Lys Asp Val Cys 305 310 315 AAA AAC TAT GCT GAG GCA AAG GAT GTC TTC CTG GGC ATG TTT TTG TAT 1068 Lys Asn Tyr Ala Glu Ala Lys Asp Val Phe Leu Gly Met Phe Leu Tyr 320 325 330 GAA TAT GCA AGA AGG CAT CCT GAT TAC TCT GTC GTG CTG CTG CTG AGA 1116 Glu Tyr Ala Arg Arg His Pro Asp Tyr Ser Val Val Leu Leu Leu Arg 335 340 345 CTT GCC AAG ACA TAT GAA ACC ACT CTA GAG AAG TGC TGT GCC GCT GCA 1164 Leu Ala Lys Thr Tyr Glu Thr Thr Leu Glu Lys Cys Cys Ala Ala Ala 350 355 360 GAT CCT CAT GAA TGC TAT GCC AAA GTG TTC GAT GAA TTT AAA CCT CTT 1212 Asp Pro His Glu Cys Tyr Ala Lys Val Phe Asp Glu Phe Lys Pro Leu 365 370 375 380 GTG GAA GAG CCT CAG AAT TTA ATC AAA CAA AAT TGT GAG CTT TTT GAG 1260 Val Glu Glu Pro Gin Asn Leu lie Lys Gin Asn Cys Glu Leu Phe Glu 385 390 395 CAG CTT GGA GAG TAC AAA TTC CAG AAT GCG CTA TTA GTT CGT TAC ACC 1308 Gin Leu Gly Glu Tyr Lys Phe Gin Asn Ala Leu Leu Val Arg Tyr Thr 400 405 410 AAG AAA GTA CCC CAA GTG TCA ACT CCA ACT CTT GTA GAG GTC TCA AGA 1356 Lys Lys Val Pro Gin Val Ser Thr Pro Thr Leu Val Glu Val Ser Arg 415 420 425 AAC CTA GGA AAA GTG GGC AGC AAA TGT TGT AAA CAT CCT GAA GCA AAA 1404 Asn Leu Gly Lys Val Gly Ser Lys Cys Cys Lys His Pro Glu Ala Lys 430 435 440 AGA ATG CCC TGT GCA GAA GAC TAT CTA TCC GTG GTC CTG AAC CAG TTA 1452 Arg Met Pro Cys Ala Glu Asp Tyr Leu Ser Val Val Leu Asn Gin Leu 445 450 455 460 TGT GTG TTG CAT GAG AAA ACG CCA GTA AGT GAC AGA GTC ACC AAA TGC 1500 Cys Val Leu His Glu Lys Thr Pro Val Ser Asp Arg Val Thr Lys Cys 465 470 475 TGC ACA GAA TCC TTG GTG AAC AGG CGA CCA TGC TTT TCA GCT CTG GAA 1548 Cys Thr Glu Ser Leu Val Asn Arg Arg Pro Cys Phe Ser Ala Leu Glu 480 485 490 GTC GAT GAA ACA TAC GTT CCC AAA GAG TTT AAT GCT GAA ACA TTC ACC 1596 Val Asp Glu Thr Tyr Val Pro Lys Glu Phe Asn Ala Glu Thr Phe Thr 495 500 505 TTC CAT GCA GAT ATA TGC ACA CTT TCT GAG AAG GAG AGA CAA ATC AAG 1644 Phe His Ala Asp lie Cys Thr Leu Ser Glu Lys Glu Arg Gin lie Lys 510 515 520 AAA CAA ACT GCA CTT GTT GAG CTC GTG AAA CAC AAG CCC AAG GCA ACA 1692 Lys Gin Thr Ala Leu Val Glu Leu Val Lys His Lys Pro Lys Ala Thr 525 530 535 540 AAA GAG CAA CTG AAA GCT GTT ATG GAT GAT TTC GCA GCT TTT GTA GAG 1740 Lys Glu Gin Leu Lys Ala Val Met Asp Asp Phe Ala Ala Phe Val Glu 545 550 555 AAG TGC TGC AAG GCT GAC GAT AAG GAG ACC TGC TTT GCC GAG GAG GGT 1788 Lys Cys Cys Lys Ala Asp Asp Lys Glu Thr Cys Phe Ala Glu Glu Gly 560 565 570 AAA AAA CTT GTT GCT GCA AGT CAA GCT GCC TTA GGC TTA TAA 1830 Lys Lys Leu Val Ala Ala Ser Gin Ala Ala Leu Gly Leu 575 580 585 (2) INFORMATION FOR SEQ ID NO: 2: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 585 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 2: Asp Ala His Lys Ser Glu Val Ala His Arg Phe Lys Asp Leu Gly Glu 1 5 10 15 Glu Asn Phe Lys Ala Leu Val Leu lie Ala Phe Ala Gin Tyr Leu Gin 20 25 30 Gin Cys Pro Phe Glu Asp His Val Lys Leu Val Asn Glu Val Thr Glu 35 40 45 Phe Ala Lys Thr Cys Val Ala Asp Glu Ser Ala Glu Asn Cys Asp Lys 50 55 60 Ser Leu His Thr Leu Phe Gly Asp Lys Leu Cys Thr Val Ala Thr Leu 65 70 75 80 Arg Glu Thr Tyr Gly Glu Met Ala Asp Cys Cys Ala Lys Gin Glu Pro 85 90 95 Glu Arg Asn Glu Cys Phe Leu Gin His Lys Asp Asp Asn Pro Asn Leu 100 105 110 Pro Arg Leu Val Arg Pro Glu Val Asp Val Met Cys Thr Ala Phe His 115 120 125 Asp Asn Glu Glu Thr Phe Leu Lys Lys Tyr Leu Tyr Glu lie Ala Arg 130 135 140 Arg His Pro Tyr Phe Tyr Ala Pro Glu Leu Leu Phe Phe Ala Lys Arg 145 150 155 160 Tyr Lys Ala Ala Phe Thr Glu Cys Cys Gin Ala Ala Asp Lys Ala Ala 165 170 175 Cys Leu Leu Pro Lys Leu Asp Glu Leu Arg Asp Glu Gly Lys Ala Ser 180 185 190 Ser Ala Lys Gin Arg Leu Lys Cys Ala Ser Leu Gin Lys Phe Gly Glu 195 200 205 Arg Ala Phe Lys Ala Trp Ala Val Ala Arg Leu Ser Gin Arg Phe Pro 210 215 220 Lys Ala Glu Phe Ala Glu Val Ser Lys Leu Val Thr Asp Leu Thr Lys 225 230 235 240 Val His Thr Glu Cys Cys His Gly Asp Leu Leu Glu Cys Ala Asp Asp 245 250 255 Arg Ala Asp Leu Ala Lys Tyr lie Cys Glu Asn Gin Asp Ser lie Ser 260 265 270 Ser Lys Leu Lys Glu Cys Cys Glu Lys Pro Leu Leu Glu Lys Ser His 275 280 285 Cys lie Ala Glu Val Glu Asn Asp Glu Met Pro Ala Asp Leu Pro Ser 290 295 300 Leu Ala Ala Asp Phe Val Glu Ser Lys Asp Val Cys Lys Asn Tyr Ala 305 310 315 320 Glu Ala Lys Asp Val Phe Leu Gly Met Phe Leu Tyr Glu Tyr Ala Arg 325 330 335 Arg His Pro Asp Tyr Ser Val Val Leu Leu Leu Arg Leu Ala Lys Thr 340 345 350 Tyr Glu Thr Thr Leu Glu Lys Cys Cys Ala Ala Ala Asp Pro His Glu 355 360 365 Cys Tyr Ala Lys Val Phe Asp Glu Phe Lys Pro Leu Val Glu Glu Pro 370 375 380 Gin Asn Leu lie Lys Gin Asn Cys Glu Leu Phe Glu Gin Leu Gly Glu 385 390 395 400 Tyr Lys Phe Gin Asn Ala Leu Leu Val Arg Tyr Thr Lys Lys Val Pro 405 410 415 Gin Val Ser Thr Pro Thr Leu Val Glu Val Ser Arg Asn Leu Gly Lys 420 425 430 Val Gly Ser Lys Cys Cys Lys His Pro Glu Ala Lys Arg Met Pro Cys 435 440 445 Ala Glu Asp Tyr Leu Ser Val Val Leu Asn Gin Leu Cys Val Leu His 450 455 460 Glu Lys Thr Pro Val Ser Asp Arg Val Thr Lys Cys Cys Thr Glu Ser 465 470 475 480 Leu Val Asn Arg Arg Pro Cys Phe Ser Ala Leu Glu Val Asp Glu Thr 485 490 495 Tyr Val Pro Lys Glu Phe Asn Ala Glu Thr Phe Thr Phe His Ala Asp 500 505 510 lie Cys Thr Leu Ser Glu Lys Glu Arg Gin lie Lys Lys Gin Thr Ala 515 520 525 Leu Val Glu Leu Val Lys His Lys Pro Lys Ala Thr Lys Glu Gin Leu 530 535 540 Lys Ala Val Met Asp Asp Phe Ala Ala Phe Val Glu Lys Cys Cys Lys 545 550 555 560 Ala Asp Asp Lys Glu Thr Cys Phe Ala Glu Glu Gly Lys Lys Leu Val 565 570 575 Ala Ala Ser Gin Ala Ala Leu Gly Leu 580 585 (2) INFORMATION FOR SEQ ID NO: 3: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 5 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iii) ANTI-SENSE: NO (v) FRAGMENT TYPE: internal (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 3: Arg Tyr Thr Lys Lys 1 5 (2) INFORMATION FOR SEQ ID NO: 4: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 5 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iii) ANTI-SENSE: NO (v) FRAGMENT TYPE: internal (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 4: Ala Tyr Thr Gin Gin 1 5 (2) INFORMATION FOR SEQ ID NO: 5: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 39 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: DNA (genomic) (iii) HYPOTHETICAL: NO (iii) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 5: CGTCAGACCT TGCATGCAGC CAAGACACCC TCACATAGC 39 (2) INFORMATION FOR SEQ ID NO: 6: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 42 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: DNA (genomic) (iii) HYPOTHETICAL: NO (iii) ANTI-SENSE: YES (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 6: CCGTTACGTT CTGTGGTGGC ATGCCCACTT CCAAGTCCAC CG 42 (2) INFORMATION FOR SEQ ID NO: 7: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 42 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: DNA (genomic) (iii) HYPOTHETICAL: NO (iii) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 7: GCGTCTCATA GTGGAAAAGC TTCTAAATAC GACAACTTCC CC 42 (2) INFORMATION FOR SEQ ID NO: 8: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 41 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: DNA (genomic) (iii) HYPOTHETICAL: NO (iii) ANTI-SENSE: YES (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 8: CCCAAAATGG TACCTGTGTC ATCACTCGTT GGGATAATAC C 41 (2) INFORMATION FOR SEQ ID NO: 9: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 44 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: DNA (genomic) (iii) HYPOTHETICAL: NO (iii) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 9: CCATCTGGAT CCAATGGTGC TTTGGCCAAA TAAATAGTTT CAGC 44 (2) INFORMATION FOR SEQ ID NO: 10: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 35 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: DNA (genomic) (iii) HYPOTHETICAL: NO (iii) ANTI-SENSE: YES (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 10: GCTTCTTTTA CCGGTAACAA GCTTGAGTCC ATTGG 35 (2) INFORMATION FOR SEQ ID NO: 11: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 37 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: DNA (genomic) (iii) HYPOTHETICAL: NO (iii) ANTI-SENSE: NO (xi) SEQUENCE DESCF '.PTION: SEQ ID NO: 11: GGTAAGGTTT AGTCGACCTA TTTTTTGTTT TGTCTGC 37 (2) INFORMATION FOR SEQ ID NO: 12: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 44 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: DNA (genomic) (iii) HYPOTHETICAL: NO (iii) ANTI-SENSE: YES (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 12: GGAAACGTAT GAATTCGATA TCATTGATAC AGACTCTGAG TACG 44 (2) INFORMATION FOR SEQ ID NO: 13: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 24 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) 'HYPOTHETICAL: NO (iii) ANTI-SENSE: NO (v) FRAGMENT TYPE: N-terminal (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 13: Met Leu Leu Gin Ala Phe Leu Phe Leu Leu Ala Gly Phe Ala Ala Lys 1 5 10 15 lie Ser Ala Asp Ala His Lys Ser 20 (2) INFORMATION FOR SEQ ID NO: 14: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 4106 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: DNA (genomic) (iii) HYPOTHETICAL: NO (iii) ANTI-SENSE: NO (vi) ORIGINAL SOURCE: (A) ORGANISM: Saccharomyces cerevisiae (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 14: GAATTCTCTG TTGACTACTA AACTGAGAGA ATTTGCCGAG ACTCTAAGAA CAGCTTTGAA 60 AGAGCGTTCT GCCGATGATT CCATAATTGT CACTCTGAGA GAGCAAATGC AAAGAGAAAT 120 CTTCAGGTTG ATGTCGTTGT TCATGGACAT ACCTCCAGTG CAACCAAACG AGCAATTCAC 180 TTGGGAATAC GTTGACAAAG ACAAGAAAAT CCACACTATC AAATCGACTC CGTTAGAATT 240 TGCCTCCAAA TACGCAAAAT TGGACCCTTC CACGCCAGTC TCATTGATCA ATGATCCAAG 300 ACACCATATG GTAAATTAAT TAAGATCGAT CGTTTAGGAA ACGTCCTTGG CGGAGATGCC 360 GTGATTTACT TAAATGTTGA CAATGAAACA CTATCTAAAT TGGTTGTTAA GAGATTACAA 420 AATAACAAAG CTGTCTTTTT TGGATCTCAC ACTCCAAAGT TCATGGACAA GAAAACTGGT 480 GTCATGGATA TTGAATTGTG GAACTATCCT GCCATGGCTA TAATTTACCT CAGCAAAAGG 540 CATCCGGTAT TAGATACCAT GAAAGTTTGA TGACTCATGC TATGTTGGAT CACTGGCTGC 600 CACGTCGATG AAACGTCTAA ATTACCACTT CGCTACCGTC TGAAAATTCC TGGGGTAAAG 660 ACTCCGGTAA AGACGGATTA TACGTGATGA CTCAAAAGTA CTTCGAGGAG TACTGCTTTC 720 AAATTGTGGT CGATATCAAT GAATTGCCAA AAGAGCTGGC TTCAAAATTC ACCTCAGGTA 780 AGGAAGAGCC GATTGTCTTG CCCATCTGGA CCCAATGGTG CTTTGGCCAA ATAAATAGTT 840 TCAGCAGCTC TGATGTAGAT ACACGTATCT CGACATGTTT TATTTTTACT ATACATACAT 900 AAAAGAAATA AAAAATGATA ACGTGTATAT TATTATTCAT ATAATCAATG AGGGTCATTT 960 TCTGAAACGC AAAAAACGGT AAATGGAAAA AAAATAAAGA TAGAAAAAGA AAACAAACAA 1020 AGGAAAGGTT AGCATATTAA ATAACTGAGC TGATACTTCA ACAGCATCGC TGAAGAGAAC 1080 AGTATTGAAA CCGAAACATT TTCTAAAGGC AAACAAGGTA CTCCATATTT GCTGGACGTG 1140 TTCTTTCTCT CGTTTCATAT GCATAATTCT GTCATAAGCC TGTTCTTTTT CCTGGCTTAA 1200 ACATCCCGTT TTGTAAAAGA GAAATCTATT CCACATATTT CATTCATTCG GCTACCATAC 1260 TAAGGATAAA CTAATCCCGT TGTTTTTTGG CCTCGTCACA TAATTATAAA CTACTAACCC 1320 ATTATCAGAT GAAAGTGAGG AAATATATTA CTTTATGCTT TTGGTGGGCC TTTTCAACAT 1380 CCGCTCTTGT ATCATCACAA CAAATTCCAT TGAAGGACCA TACGTCACGA CAGTATTTTG 1440 CTGTAGAAAG CAATGAAACA TTATCCCGCT TGGAGGAAAT GCATCCAAAT TGGAAATATG 1500 AACATGATGT TCGAGGGCTA CCAAACCATT ATGTTTTTTC AAAAGAGTTG CTAAAATTGG 1560 GCAAAAGATC ATCATTAGAA GAGTTACAGG GGGATAACAA CGACCACATA TTATCTGTCC 1620 ATGATTTATT CCCGCGTAAC GACCTATTTA AGAGACTACC GGTGCCTGCT CCACCAATGG 1680 ACTCAAGCTT GTTACCGGTA AAAGAAGCTG AGGATAAACT CAGCATAAAT GATCCGCTTT 1740 TTGAGAGGCA GTGGCACTTG GTCAATCCAA GTTTTCCTGG CAGTGATATA AATGTTCTTG 1800 ATCTGTGGTA CAATAATATT ACAGGCGCAG GGGTCGTGGC TGCCATTGTT GATGATGGCC 1860 TTGACTACGA AAATGAAGAC TTGAAGGATA ATTTTTGCGC TGAAGGTTCT TGGGATTTCA 1920 ACGACAATAC CAATTTACCT AAACCAAGAT TATCTGATGA CTACCATGGT ACGAGATGTG 1980 CAGGTGAAAT AGCTGCCAAA AAAGGTAACA ATTTTTGCGG TGTCGGGGTA GGTTACAACG 2040 CTAAAATCTC AGGCATAAGA ATCTTATCCG GTGATATCAC TACGGAAGAT GAAGCTGCGT 2100 CCTTGATTTA TGGTCTAGAC GTAAACGATA TATATTCATG CTCATGGGGT CCCGCTGATG 2160 ACGGAAGACA TTTACAAGGC CCTAGTGACC TGGTGAAAAA GGCTTTAGTA AAAGGTGTTA 2220 CTGAGGGAAG AGATTCCAAA GGAGCGATTT ACGTTTTTGC CAGTGGAAAT GGTGGAACTC 2280 GTGGTGATAA TTGCAATTAC GACGGCTATA CTAATTCCAT ATATTCTATT ACTATTGGGG 2340 CTATTGATCA CAAAGATCTA CATCCTCCTT ATTCCGAAGG TTGTTCCGCC GTCATGGCAG 2400 TCACGTATTC TTCAGGTTCA GGCGAATATA TTCATTCGAG TGATATCAAC GGCAGATGCA 2460 GTAATAGCCA CGGTGGAACG TCTGCGGCTG CTCCATTAGC TGCCGGTGTT TACACTTTGT 2520 TACTAGAAGC CAACCCAAAC CTAACTTGGA GAGACGTACA GTATTTATCA ATCTTGTCTG 2580 CGGTAGGGTT AGAAAAGAAC GCTGACGGAG ATTGGAGAGA TAGCGCCATG GGGAAGAAAT 2640 ACTCTCATCG CTATGGCTTT GGTAAAATCG ATGCCCATAA GTTAATTGAA ATGTCCAAGA 2700 CCTGGGAGAA TGTTAACGCA CAAACCTGGT TTTACCTGCC AACATTGTAT GTTTCCCAGT 2760 CCACAAACTC CACGGAAGAG ACATTAGAAT CCGTCATAAC CATATCAGAA AAAAGTCTTC 2820 AAGATGCTAA CTTCAAGAGA ATTGAGCACG TCACGGTAAC TGTAGATATT GATACAGAAA 2880 TTAGGGGAAC TACGACTGTC GATTTAATAT CACCAGCGGG GATAATTTCA AACCTTGGCG 2940 TTGTAAGACC AAGAGATGTT TCATCAGAGG GATTCAAAGA CTGGACATTC ATGTCTGTAG 3000 CACATTGGGG TGAGAACGGC GTAGGTGATT GGAAAATCAA GGTTAAGACA ACAGAAAATG 3060 GACACAGGAT TGACTTCCAC AGTTGGAGGC TGAAGCTCTT TGGGGAATCC ATTGATTCAT 3120 CTAAAACAGA AACTTTCGTC TTTGGAAACG ATAAAGAGGA GGTTGAACCA GCTGCTACAG 3180 AAAGTACCGT ATCACAATAT TCTGCCAGTT CAACTTCTAT TTCCATCAGC GCTACTTCTA 3240 CATCTTCTAT CTCAATTGGT GTGGAAACGT CGGCCATTCC CCAAACGACT ACTGCGAGTA 3300 CCGATCCTGA TTCTGATCCA AACACTCCTA AAAAACTTTC CTCTCCTAGG CAAGCCATGC 3360 ATTATTTTTT AACAATATTT TTGATTGGCG CCACATTTTT GGTGTTATAC TTCATGTTTT 3420 TTATGAAATC AAGGAGAAGG ATCAGAAGGT CAAGAGCGGA AACGTATGAA TTCGATATCA 3480 TTGATACAGA CTCTGAGTAC GATTCTACTT TGGACAATGG AACTTCCGGA ATTACTGAGC 3540 CCGAAGAGGT TGAGGACTTC GATTTTGATT TGTCCGATGA AGACCATCTT GCAAGTTTGT 3600 CTTCATCAGA AAACGGTGAT GCTGAACATA CAATTGATAG TGTACTAACA AACGAAAATC 3660 CATTTAGTGA CCCTATAAAG CAAAAGTTCC CAAATGACGC CAACGCAGAA TCTGCTTCCA 3720 ATAAATTACA AGAATTACAG CCTGATGTTC CTCCATCTTC CGGACGATCG TGATTCGATA 3780 TGTACAGAAA GCTTCAAATT ACAAAATAGC ATTTTTTTCT TATAGATTAT AATACTCTCT 3840 CATACGTATA CGTATATGTG TATATGATAT ATAAACAAAC ATTAATATCC TATTCCTTCC 3900 GTTTGAAATC CCTATGATGT ACTTTGCATT GTTTGCACCC GCGAATAAAA TGAAAACTCC 3960 GAACCGATAT ATCAAGCACA TAAAAGGGGA GGGTCCAATT AATGCATATT TAAGACCACA 4020 GCTGAATAAC TTTAAAACGG CAGACAAAAC AAAAAATAGG TCGAATAAAC CTTACCTGCC 4080 TAGAAGGAAT GACAGCAGCT AATAAG 4106 (2) INFORMATION FOR SEQ ID NO: 15: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 2526 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: DNA (genomic) (iii) HYPOTHETICAL: NO (iii) ANTI-SENSE: NO (vi) ORIGINAL SOURCE: (A) ORGANISM: Saccharomyces cerevisiae (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 15: CCGTTTTCTT TTCGTAAAAA AAAACAATAG ACACTATATA TAGACACTTT TTCCTTTCCT 60 TCTTTGCGCG ATTTCAAGAG GAAAAGCATA CTTAAATAAG AATATTCCTA AAACACACGT 120 TCTGACGCGT CAATTAGATC GTCAGACCTT GCATGCAGCC AAGACACCCT CACATAGCAC 180 TGCCTCCTTC CTCCTCTTTT CTGTCACCAC CTCACCTCCC TCGTCCACTC AACTGAGTGG 240 CTTTTCGCTC CTTTTATACT GCGCCATGAG TAGTTTTCGT TTCACTGATG TGTCCGAAAA 300 AATTGAGGTT TCATAAAAAA ATTCGTGGAC TTATTTATGG AGAAACAGGG AAATCCGACT 360 ACTTAAGAAA AGGGTGTCAA AGAGGATTTA CTTTTTTCCT TCTTTTTGCA TTTGTTCCTA 420 TTTCCGCAAT TGGACGGTTA TTAAGAAGAA CGCAATTGGC TTTTCTGTAT ATTAAAATAC 480 ATAGCGTAAT AAAAAGATAA GGTGAACACC AAGCATATAG TATAATATTA CCTACCACAT 540 ATGAAACTGA AAACTGTAAG ATCTGCGGTC CTTTCGTCAC TCTTTGCATC GCAGGTTCTC 600 GGTAAGATAA TACCAGCAGC AAACAAGCGC GACGACGACT CGAATTCCAA GTTCGTCAAG 660 TTGCCCTTTC ATAAGCTTTA CGGGGACTCG CTAGAAAATG TGGGAAGCGA CAAAAAACCG 720 GAAGTACGCC TATTGAAGAG GGCTGACGGT TATGAAGAAA TTATAATTAC CAACCAGCAA 780 AGTTTCTATT CGGTGGACTT GGAAGTGGGC ACGCCACCAC AGAACGTAAC GGTCCTGGTG 840 GACACAGGCT CCTCTGATCT ATGGATTATG GGCTCGGATA ATCCATACTG TTCTTCGAAC 900 AGTATGGGTA GTAGCCGGAG ACGTGTTATT GACAAACGTG ATGATTCGTC AAGCGGCGGA 960 TCTTTGATTA ATGATATAAA CCCATTTGGC TGGTTGACGG GAACGGGCAG TGCCATTGGC 1020 CCCACTGCTA CGGGCTTAGG AGGCGGTTCA GGTACGGCAA CTCAATCCGT GCCTGCTTCG 1080 GAAGCCACCA TGGACTGTCA ACAATACGGG ACATTTTCCA CTTCGGGCTC TTCTACATTT 1140 AGATCAAACA ACACCTATTT CAGTATTAGC TACGGTGATG GGACTTTTGC CTCCGGTACT 1200 TTTGGTACGG ATGTTTTGGA TTTAAGCGAC TTGAACGTTA CCGGGTTGTC TTTTGCCGTT 1260 GCCAATGAAA CGAATTCTAC TATGGGTGTG TTAGGTATTG GTTTGCCCGA ATTAGAAGTC 1320 ACTTATTCTG GCTCTACTGC GTCTCATAGT GGAAAAGCTT ATAAATACGA CAACTTCCCC 1380 ATTGTATTGA AAAATTCTGG TGCTATCAAA AGCAACACAT ATTCTTTGTA TTTGAACGAC 1440 TCGGACGCTA TGCATGGCAC CATTTTGTTC GGAGCCGTGG ACCACAGTAA ATATACCGGC 1500 ACCTTATACA CAATCCCCAT CGTAAACACT CTGAGTGCTA GTGGATTTAG CTCTCCCATT 1560 CAATTTGATG TCACTATTAA TGGTATCGGT ATTAGTGATT CTGGGAGTAG TAACAAGACC 1620 TTGACTACCA CTAAAATACC TGCTTTGTCG GATTCCGGTA CTACTTTGAC TTATTTACCT 1680 CAAACAGTGG TAAGTATGAT CGCTACTGAA CTAGGTGCGC AATACTCTTC CAGGATAGGG 1740 TATTACGTAT TGGACTGTCC ATCTGATGAT AGTATGGAAA TAGTGTTCGA TTTTGGTGGT 1800 TTTCACATCA ATGCACCACT TTCGAGTTTT ATCTTGAGTA CTGGCACTAC ATGTCTTTTA 1860 GGTATTATCC CAACGAGTGA TGACACAGGT ACCATTTTGG GTGATTCATT TTTGACTAAC 1920 GCGTACGTGG TTTATGATTT GGAGAATCTT GAAATATCCA TGGCACAAGC TCGCTATAAT 1980 ACCACAAGCG AAAATATCGA AATTATCACA TCCTCTGTTC CAAGCGCCGT AAAGGCACCA 2040 GGCTATACAA ACACTTGGTC CACAAGTGCA TCTATTGTTA CCGGTGGTAA CATATTTACT 2100 GTAAATTCCT CACAAACTGC TTCCTTTAGC GGTAACCTGA CGACCAGTAC TGCATCCGCC 2160 ACTTCTACAT CAAGTAAAAG AAATGTTGGT GATCATATAG TTCCATCTTT ACCCCTCACA 2220 TTAATTTCTC TTCTTTTTGC ATTCATCTGA AAACCGTTGC ACAAAGTTTA GACATTCACA 2280 TCTCCAAGCC AGTTGGAGTT TCTGGCGGAA ATCGTTGCTC TCGCTTGGGC AAAGTTTTTT 2340 TTTATTATTA ATTTTTTATT GTTACGTTGG CGGTCTTTAT TTTTACTTCA CAATAGTTTA 2400 TCTTACCCAC TAAG ATAGG TTACCATTTA TTCACATTTT TTTTTCTCAT TCCTAGTATA 2460 CTATTTACCT GGGATATGGC CTATAATCAA AGGCTTTAAT ATTCTAATAA TTCGTTTGGC 2520 ATCTAG 2526

Claims: CLAIMS 1. A process for preparing albumin by secretion from a yeast genetically modified to produce and secrete the albumin, comprising culturing the yeast in a culture medium such that albumin is secreted into the medium, characterised in that the yeast cells have a reduced level of yeast aspartyl protease 3 proteolytic activity. 2. A process according to Claim 1 wherein the said proteolytic activity is an endoprotease activity specific for monobasic sites and for paired basic amino acids in a polypeptide. 3. A process according to Claim 1 or 2 wherein the yeast is S. cerevisiae. 4. A process according to Claim 1, 2 or 3 wherein the yeast lacks a functional YAP3 gene or homologue thereof. 5. A process according to any one of Claims 1 to 4 wherein the yeast cells additionally have a reduced level of S. cerevisiae Kex2p proteolytic activity. 6. A process according to any one of the preceding claims wherein the albumin is a human albumin. 7. A culture of yeast cells containing a polynucleotide sequence encoding an albumin and a second polynucleotide sequence encoding a secretion signal causing albumin expressed from the first polynucleotide sequence to be secreted from the yeast, characterised in that the yeast cells have a reduced level of yeast aspartyl protease 3 proteolytic activity. 8. A culture according to Claim 7 wherein the albumin is a human albumin. 9. A culture according to Claim 7 or 8 wherein the yeast is S. cerevisiae. 10. A culture according to any one of Claims 7 to 9 wherein the said signal is cleaved by the yeast prior to release of the albumin from the yeast. 11. A culture according to any one of Claims 7 to 10 wherein the yeast cells additionally have a reduced level of Kex2p proteolytic activity. 12. A culture according to Claim 11 wherein the said secretion signal is cleaved from the albumin by a protease other than Kex2p. 13. A modified albumin having at least 90% sequence identity to a naturally-occurring albumin, which naturally-occurring albumin is susceptible to cleavage with yeast aspartyl protease 3 (Yap3p) when expressed and secreted in yeast, characterised in that the modified albumin is not susceptible to such cleavage. 14. A modified albumin according to Claim 13 wherein the modified albumin lacks a monobasic amino acid present in the naturally- occurring albumin protein. 15. A modified albumin according to Claim 13 or 14 wherein the said monobasic amino acid is arginine. 16. A modified albumin according to Claim 14 or 15 wherein the modified albumin additionally lacks a pair of basic amino acids present in the naturally-occurring albumin. 17. A modified albumin according to Claim 16 wherein the said pair of amino acids is Lys, Lys; Lys, Arg; Arg, Lys; or Arg, Arg. 18. A modified albumin according to Claim 13 wherein the naturally- occurring albumin is a human albumin and the modified protein lacks Arg 410 ; and, optionally, residues 413 and 414 do not each consist of lysine or arginine. 19. A modified albumin according to Claim 18 which is a human albumin having the amino acid changes R410A, K413Q, K414Q. 20. A polynucleotide encoding a modified albumin according to any one of Claims 13 to 19. 21. A yeast containing a polynucleotide according to Claim 20, transcription signals such that the modified albumin is expressed in the yeast, and a further polynucleotide adjacent the said polynucleotide such that the modified albumin is secreted from the yeast.

Inventors: GILBERT SARAH CATHERINE, KERRY-WILLIAMS SEAN MARTIN, GILBERT, SARAH, CATHERINE, KERRY-WILLIAMS, SEAN, MARTIN
Applicants: DELTA BIOTECHNOLOGY LTD, GILBERT SARAH CATHERINE, KERRY WILLIAMS SEAN MARTIN, DELTA BIOTECHNOLOGY LIMITED, GILBERT, SARAH, CATHERINE, KERRY-WILLIAMS, SEAN, MARTIN
Application year: 1995
Main classification: C12N15
IPC codes: A61K38, A61P9, A61P43, C07K14, C12N1, C12N9, C12N15, C12P21, C12R1