bluuebunny/crossref_metadata_2025_split huggingface dataset:
Subunit Structure of L‐Lactate Dehydrogenase (Cytochrome b2) of Saccharomyces cerevisiae
Authors: Mevel‐Ninio Maryvonne 
Published: March 2005

The molecular weights of yeast L‐lactate dehydrogenase (cytochrome b2) and of its polypeptide chains have been measured by ultracentrifugation. The intact protein was found to have a molecular weight of 240000 ± 10000 by sedimentation equilibrium measurements according to the Yphantis high‐speed method. The solution obtained by dissolving the protein in 6 M guanidine (with added 2‐mercaptoethanol) behaved as if it were monodisperse, giving Mr= 31300 ± 2000, by approach‐to‐equilibrium measurements. This result indicates that the “58 600 unit” associated to one set of prosthetic groups, heme and flavin, is made up of two chains, and thus the whole molecule contains a total of eight chains, identical or not. However, as the viscosity of the medium was reduced (using 2 M guanidine) the paucidispersity of the cytochrome b2 solution was revealed. The mixture was shown to consist of two kinds of chains distinct in molecular weight. From these experiments the molecular weight of the light chain was found to be 22600 ± 1500. After partial separation of the two chains by gel filtration through Sephadex G‐100, the molecular weight of the heavy chain was estimated as 39700 ± 3000.Preliminary experiments indicate that the heavy component can bind quantitatively the heme prosthetic group. The FMN appears to be bound to the light component.
Precipitation of Lipopolysaccharides from Rough Mutants of Salmonella typhimurium by an A‐Hemagglutinin from Helix pomatia
Authors: Hammarström Sten , Lindberg Alf A. , Robertsson Eva Stina 
Published: March 2005

Purified Helix pomatia A‐hemagglutinin precipitated lipopolysaccharides of Salmonella typhimurium rough mutants of chemotype Ra and Rb. No precipitation was obtained with lipopoly‐saccharide of the parent smooth strain or of Rc, Rd and Re mutants or with isolated lipid A. Reactivity of lipopolysaccharide from some of the Ra and Rb mutants was increased when precipitated in a mixture of tetrahydrofuran—phosphate‐buffered saline (1:3, by vol.). However lipopolysaccharide from nonreactive mutants was still negative in the latter medium. Precipitating ability of lipopolysaccharide from Ra and Rb mutants was retained after treatment of the lipopolysaccharide with sodium borohydride (or NaOH).Precipitation was inhibited by N‐acetyl‐D‐galactosamine but not as easily by D‐galactose or D‐mannose. The lipopolysaccharide from the Ra mutant TV160 displaced a labelled blood‐group‐A‐active pentasaccharide from the combining site of the hemagglutinin. Inhibition studies indicated that the interaction was weak.Core polysaccharides prepared by acid hydrolysis and gel filtration from the lipopolysaccharide of the Ra mutant SH180 and the Rb mutant TV160 inhibited precipitation. On a molar basis the SH180 core polysaccharide was approximately as active as α‐D‐Gal‐(1→6)‐D‐Glc while the TV160 fragment was five times more active.The precipitating ability of TV160 lipopolysaccharide was abolished after treatment with the enzyme D‐galactose oxidase.The structural element in the core region in common for all reactive lipopolysaccharide is nonreducing D‐Gal linked α(1→6) to D‐Glc. It is suggested that this residue is the “immunodominant” sugar responsible for precipitation. In the TV160 lipopolysaccharide there is an additional nonreducing D‐Gal residue linked α(1→3) to the same D‐Glc. It is possible that the presence of this residue increases the binding.The experiments suggest that precipitation occurs when both reagents are polyvalent although each individual interaction may be very weak.
Recherches biochimiques sur l'oogenése
Authors: Denis Herman , Mairy Marianne 
Published: March 2005

As found previously, 70 to 75% of the RNA present in previtellogenic oocytes of Xenopus laevis (average diameter: 50 to 150 μm) is 5‐S RNA and transfer RNA. In this paper, we show that most of the RNA of the small oocytes is stored in nucleoprotein particles sedimenting at 58 S and 42 S. These particles are no longer detectable in vitellogenic oocytes (average diameter: 375 to 1100 μm) which accumulate ribosomes very rapidly.The 58‐S particles contain mainly high‐molecular‐weight RNA. This RNA has a base composition close to that of DNA. Its main component sediments at about 19 S. The 42‐S particles contain more than half of the RNA and a quarter of the protein present in homogenates of small oocytes. The only RNA species found in the 42‐S particles are 5‐S RNA and tRNA. The molar ratio of tRNA to 5‐S RNA in the 42‐S particles is 3:1.5‐S RNA is distributed as follows in the small oocytes: less than 1% of the total cell content is bound to the ribosomes; about 50% is in the 42‐S particles and the remainder is apparently free in the cell sap. By its base composition and its hybridization properties 5‐S RNA from the 42‐S particles cannot be distinguished from 5‐S RNA of the cell sap and from 5‐S RNA of somatic cells.About 90% of the total tRNA content of the oocyte is included in the 42‐S particles. The remaining 10% is either free or bound to the ribosomes. No difference was noticed in the hybridization properties of tRNA which is inside the 42‐S particles and tRNA which is outside these particles.The 42‐S particles present in homogenates of previtellogenic oocytes are not artifacts. These particles are probably storage particles in which 5‐S RNA and tRNA produced in excess during the initial period of oogenesis are kept for many months until the ribosomes begin to accumulate. The role of the 58‐S particles remains unknown.
Recherches biochimiques sur l'oogenèse
Authors: Mairy Marianne , Denis Herman 
Published: March 2005

Almost half of the RNA present in previtellogenic oocytes of Xenopus laevis is 5‐S RNA. Less than 1% of this RNA is immediately included in the ribosomes. 5‐S RNA made in excess in the small oocytes is not degraded but stored and progressively taken up by the ribosomes which accumulate very rapidly after the beginning of vitellogenesis.The amount of 5‐S RNA stored in the small oocyte is not sufficient to meet the needs of the cell until the end of its growth since 5‐S RNA continues to be synthesized during the second part of oogenesis. The ribosomes assembled during this period incorporate both newly‐made 5‐S RNA and 5‐S RNA which has been synthesized months before. Newly‐made 5‐S RNA seems to be taken up by the ribosomes somewhat more rapidly than “old” 5‐S RNA.
Peptidyl‐Donor Substrates for Ribosomal Peptidyl Transferase
Authors: Mercer Julian F. B. , Symons Robert H. 
Published: March 2005

A study of the structural requirements for activity of low molecular weight compounds in the donor or peptidyl site of ribosomal peptidyl transferase requires methods for the chemical synthesis of potential donor substrates. Methods are described here for the preparation of cytidylyl‐(3′→ 5′)‐cytidylyl‐(3′→ 5′)‐2′(3′)‐O‐(N‐[3H]acetyl‐l‐leucyl)‐adenosine and cytidylyl‐(3′→ 5′)‐2′(3′)‐O‐(N‐[3H]acetyl‐l‐leucyl)‐adenosine and the corresponding l‐phenylalanine derivatives. A major difficulty overcome was the severe restriction placed on possible synthetic routes by the extreme alkali lability of the aminoacyl linkage. The synthetic route developed involved the stepwise synthesis of CpCpA and CpA appropriately protected with acid‐labile protecting groups. The free terminal 2′(3′)‐hydroxyls were aminoacylated, all protecting groups removed and the α‐amino groups acylated with [3H]acetic anhydride.The chemically prepared N‐acetyl‐aminoacyl‐trinucleotide fragments had similar activity in the ribosome‐catalysed fragment reaction as reported for the corresponding pentanucleotide fragments obtained from biological sources. Further, the inactivity of the N‐acetyl‐aminoacyl‐dinucleotide fragments was confirmed under a wider range of conditions than those previously described.
Zur Biosynthese der Alkaloide vom Rhoeadin‐Typ
Authors: Rönsch Hasso 
Published: March 2005

The biosynthesis of alkaloids with 2‐phenyl‐3‐benzazepine skeleton (rhoeadine type) starts from two molecules of tyrosine. Now it was shown, using Papaver bracteatum plants, that [N‐14CH3, 8‐14C]dl‐tetrahydropalmatine methiodide (Ia) is incorporated with high efficiency into alpinigenine (III). Apparently the incorporation of the N‐quaternary salt is a specific one.
A degradation sequence was applied which allows the selective determination of the radio‐activity in the non‐aromatic C‐atoms as well as the aromatic rings of alpinigenine.
The incorporation of a compound with tetrahydroprotoberberine structure is in accordance with current biogenetic views. But involvement of a N‐quaternary intermediate seems quite surprising. A novel mechanism of ring rearrangement may operate. Thus, ring splitting as a step for further transformation of tetrahydropalmatine should be initiated by N‐methylation followed by hydroxylation on one of the α‐C‐atoms (C‐14 or C‐8) and subsequent hydrolysis.
The significance of the feeding experiments in respect to biogenesis of benzazepine alkaloids is briefly discussed.
Ribonucleic Acid Polymerase from Eukaryotic Cells
Authors: Mondal Hrishikes , Ganguly Asok , Das Asis , Mandal Radha K. , Biswas Birendra B. 
Published: March 2005

The role of protein factor B and C on RNA synthesis by RNA polymerase CI isolated from chromosomal non‐histone proteins of coconut nuclei has been studied further. Factor B has been implicated as the initiation factor on the experimental evidences that (a) in its absence, RNA polymerase CI shows only minimal activity; (b) it can bind with RNA polymerase and the enzyme · factor B complex then binds to DNA, but factor B alone can not bind to DNA; (c) it promotes the incorporation of [β,γ‐32P2]ATP into RNA and this stimulation reaches a plateau rather quickly while the incorporation of [14C]ATP in the interior of RNA chain continues; (d) it is active with native homologous DNA as template, but not with denatured or λDNA; (e) RNA molecules synthesized in its presence are of higher sedimentation value (10–20 S) than that synthesized in its absence (4 S); (f) it can completely counteract the inhibitory effect of rifampicin, which is known to inhibit RNA synthesis at the initiation step.Factor C seems to facilitate the release of synthesized RNA from the DNA template since (a) it stimulates RNA synthesis by polymerase CI when added on top of factor B, but in absence of factor B, C alone is inactive; (b) it can reinitiate RNA synthesis after the reaction has reached a plateau in a system where DNA is limiting, an affect similar to that obtained at higher ionic strength. Factor C, however, does not influence the molecular size of RNA synthesized. Furthermore, the RNA polymerase CI is sensitive to α‐amanitin whereas the RNA polymerase CII is comparatively resistant. The former appears to synthesize the non‐ribosomal RNA whereas the latter synthesizes ribosomal RNA.
Hydrogen‐Ion‐Titration Studies of Pancreatic Phospholipase A and Its Zymogen
Authors: Janssen Lambert H. M. , de Bruin Simon H. , DE Haas Gerard H. 
Published: March 2005

The titration curves of porcine pancreatic phospholipase A an its zymogen were measured in the pH region 2.0 to 9.5 at 25°C.In the pH region 2 to 6 the titration curves were measured using an Ag‐AgCl electrode as reference electrode, at ionic strength 0.5. It was found that the titration of the carboxyl groups could be described with the Linderstrøm‐Lang model using an intrinsic pKof 4.5 and an electrostatic interaction factor ω of 0.073. The side‐chain carboxyl group of the second (viz. glutamyl) residue in prophospholipase appeared to have an abnormally low pK of 3.7. The maximum positive charge of the two proteins as determined by titration agreed well with the values predicted by the amino acid composition.From an analysis of the titration curves covering the region 4.5 to 9.5, which were measured with a calomel electrode at ionic strength 0.1, the following could be concluded. The intrinsic pK and ω of the carboxyl groups appeared to be at this ionic strength 4.7 and 0.114, respectively. In both phospholipase and prophospholipase the number of titratable carboxyl groups was found to be 3 higher than given by the amino acid analysis. All 3 histidines present were titratable with an intrinsic pK of 6.6 and ω near zero. The terminal amino group which is free only in phospholipase appeared to have an apparent pK of 8.3.
The Metabolism of Benzoate and Methylbenzoates via the meta‐Cleavage Pathway by Pseudomonas arvilla mt‐2
Authors: Murray Keith , Duggleby Clive J. , Williams Peter A. , Sala‐Trepat José M. 
Published: March 2005

Pseudomonas arvilla mt‐2 grows at the expense of benzoate, m‐toluate (3‐methylbenzoate) and p‐toluate (4‐methylbenzoate), but not o‐toluate (2‐methylbenzoate). Under various conditions compounds with spectra characteristic of muconic semialdehydes can be made to accumulate in the media. These spectra indicate that benzoate is metabolised through catechol and 2‐hydroxymuconic semialdehyde (2‐hydroxy‐6‐oxohexa‐2,4‐dienoate), m‐toluate through 3‐methylcatechol and 2‐hydroxy‐6‐oxohepta‐2,4‐dienoate and p‐toluate through 4‐methylcatechol and 2‐hydroxy‐5‐methylmuconic semialdehyde (2‐hydroxy‐5‐methyl‐6‐oxohexa‐2,4‐dienoate).
Freshly harvested cells grown on all three substrates only consume oxygen at a significant rate when presented with the growth substrates themselves and catechol and the methylcatechols, but not with salicylate, protocatechuate or phenol or the cresols.
Extracts of cells grown on these substrates contain high induced levels of the suite of meta cleavage enzymes, including both the hydrolytic branch and the 4‐oxalocrotonate branch.
The substrate specificity of the early enzymes of the pathway suggests that only one non specific enzyme expresses each activity in cell‐free extracts and that it is nonspecifically induced during growth on all three carbon sources.
It is suggested that the metabolic role of the hydrolytic branch of the pathway is the assimilation of 3‐methylcatechol and its precursor, and that of the 4‐oxalocrotonate branch is to assimilate catechol and 4‐methylcatechol and their precursors.
o‐Toluate is not metabolised because it is neither a substrate for the benzoate oxidase system nor an inducer of any of the meta pathway enzymes.
It appears that benzoate and m‐and p‐‐toluates are the substrate inducers of the meta pathway enzymes in this organism. The ortho pathway is induced on incubating cells with catechol and the first inducer appears to be cis,cis‐muconate or possibly catechol itself.
A Glycopeptide from the Posterior Lobe of Pig Pituitaries
Authors: Holwerda Dirk A. 
Published: March 2005

An extract from the posterior lobes of pig pituitaries contains a glycopeptide with a molecular mass of 3200 (± 5%). The glycopeptide is present in amounts of the same order as the hormones oxytocin and vasopressin.The peptide portion is composed of seventeen amino acid residues: aspartic acid or asparagine (3), threonine (1), serine (3), proline (1), glycine (2), alanine (3), leucine (3) and arginine (1). The carbohydrate portion, about 55% by weight, is composed of fucose (1), galactose (1), mannose (3) and glucosamine (4). The glycopeptide exhibits none of the known physiological activities of hypophysis except for a slight lipolytic activity.
The Metabolic Divergence in the meta Cleavage of Catechols by Pseudomonas putida NCIB 10015
Authors: Sala‐Trepat Jose M. , Murray Keith , Williams Peter A. 
Published: March 2005

A reinvestigation of the catabolic pathway(s) used by Pseudomonas putida NCIB 10015 (Dagley's strain) for the degradation of phenol and the cresols has proved the existence of a metabolic divergence after meta cleavage of the catechols formed by hydroxylation of the primary substrates. The ring‐fission products of catechol and 4‐methylcatechol are shown to be simultaneously catabolized by two different enzymic activities, an NAD+‐dependent dehydrogenase and a cofactor‐independent hydrolase. The metabolizing activities of both ring‐fission products in extracts of cells grown on phenol and the cresols (o‐, m‐ and p‐cresol) were found to be non specific; thermal inactivation of extracts of phenol‐grown cells has shown that this nonspecificity is attributable to only one enzyme expressing each activity and that the two activities are located on separate proteins.
Extracts of cells grown on all four substrates contain high induced levels of the meta cleavage suite of enzymes functional in the dissimilation of catechol, including both the 4‐oxalocrotonate branch (NAD+‐dependent 2‐hydroxymuconic semialdehyde dehydrogenase, 4‐oxalocrotonate tautomerase and 4‐oxalocrotonate decarboxylase) and the hydrolytic branch (2‐hydroxymuconic semialdehyde hydrolase).
The hydroxylase, oxygenase, dehydrogenase and hydrolase activities are shown to be nonspecific and can also act upon the methyl derivatives of their respective substrates. A constant pattern of specificity was found for these enzymes, independent of the monophenolic substrate used for growth.
From studies with a mutant lacking phenol hydroxylase, the entire suite of meta cleavage enzymes are shown to be coincidently induced from the top by the primary substrate (phenol or the cresols).
The evolutionary and physiological implications of the divergent pathway are discussed.
Covalently Bound Flavin ind‐6‐Hydroxynicotine Oxidase fromArthrobacter oxidans
Authors: Brühmüller Margarete , Möhler Hanns , Decker Karl 
Published: March 2005

d‐6‐Hydroxynicotine oxidase fromArthrobacter oxidansgrown on citrate anddl‐nicotine was obtained as a homogeneous protein as judged by ultracentrifugation and disc electrophoresis. From the sedimentation and diffusion coefficients of 3.54 S and 6.69 F, respectively, and from sedimentation equilibrium measurements a molecular weight of 53000 was calculated.d‐6‐Hydroxynicotine oxidase consists of one polypeptide chain and contains one mol FAD per mol enzyme. The flavin was shown to be covalently bound to the protein.In the presence of oxygen,d‐6‐hydroxynicotine oxidase convertsd‐6‐hydroxynicotine to [6‐hydroxypyridyl‐(3)]‐(4‐N‐methylaminopropyl)‐ketone. Molecular oxygen could be replaced as electron acceptor by methylene blue and 2,6‐dichlorophenolindophenol, but not by one‐electron acceptors. Anaerobic reduction of the enzyme with substrate did not reveal a semiquinoid flavin intermediate. The spectral changes obtained by the photochemical reduction ofd‐6‐hydroxynicotine oxidase in the presence of EDTA, however, indicated an anionic semiquinone form.d‐6‐Hydroxynicotine oxidase proved to be highly specific for the structural and absolutely specific for the stereochemical configuration of its substrate. Among others,l‐6‐hydroxynicotine and the reaction product were found to be competitive inhibitors.
An Analysis of DNA‐Containing Particles Recovered from the Cytoplasm of Differentiating Chick‐Muscle Cells
Authors: Bell Eugene , Merrill Charlotte , Lawrence Charles B. 
Published: March 2005

Labeled DNA‐containing particles from the cytoplasm of embryonic chick muscle can be dissociated in 0.5 M KCl to a basic particle of buoyant density 1.57 g/ml in CsCl. DNA‐containing particles of density 1.43 g/ml are found in a large distribution of distinct sizes whose sedimentation values in sucrose range from 16 S to greater than 100 S. DNA‐containing particles in a range of densities centering about a peak of 1.52 g/ml are found cosedimenting with polyribosomes in sucrose. The latter particles contain at least two subunits which are dissociable by treatment with EDTA; the DNA‐containing subparticle has a density of 1.43 g/ml.Newly made RNA is found in association with DNA‐containing particles banding at 1.43 g/ml which are about 40 S and larger but not with particles of density 1.57 g/ml.Virtually all of the rapidly labeling cytoplasmic RNA taken from the polyribosomal region of a sucrose gradient is associated with particles of densities 1.43 g/ml and 1.55 g/ml; a minor portion may be associated with particles of density 1.52 g/ml which are found cosedimenting uniquely with polyribosomes.Practically all nascent chain protein is associated with particles of density 1.55 g/ml, which is the density of ribosomes or polyribosomes.Addition of labeled DNA to cytoplasmic extracts does not yield any of the foregoing particles, and no binding of label to polyribosomes or cosedimenting structures is observed. DNA‐containing particles from the nucleus band at densities different from particles recovered from the cytoplasm.We propose that the particles recovered from the cytoplasm are naturally occurring and not artifacts of fractionation and processing, and we present a model for their utilization in the transfer and use of genetic information.
Alkaline Denaturation of Nucleohistone
Authors: Ohba Yoshiki , Hayashi Masako 
Published: March 2005

The ultraviolet spectral change at 245 nm of tyrosine residues in histones in alkaline solution was studied. The difference spectrum of histones between alkaline and neutral solution yields an absorption maximum at 242 nm. However, the influence of configurational changes of backbone structure of histones in alkaline solution, results in the true peak position being located near 245 nm. This was established from artificial difference spectra between histones and N‐acetyl‐l‐tyrosine ethyl ester in 0.5 N NaOH, conditions under which ionization of phenolic hydrogens of histones is immediately complete. This ease of ionization permits the quantitative estimation of histones in nucleohistone by measuring the ratio of absorbance at 244 nm to that at 260 nm, so long as we can prepare the nucleohistone from calf thymus which does not contain non‐histone protein.Alkaline spectrophotometric titration of nucleohistone revealed that conformational changes of histones occur when the double helical structure of DNA is in the process of disruption in a nucleohistone molecule. This conformational change occurred without the dissociation of histones and DNA. The dissociation of histones and DNA in alkaline pH region was discussed.
Localization of Protein A in the Bacteria
Authors: Sjöquist John , Movitz Jan , Johansson Inga‐Britt , Hjelm Hans 
Published: March 2005

Staphylococcus aureus, strain Cowan I, contains 1.7% protein A and its isolated cell walls contain 6.7%.Removal of contaminating cytoplasmic membrane fragments from the cell walls does not decrease the content of protein A. Extraction of cell walls with trichloroacetic acid releases teichoic acid but not protein A. Extractions with high concentrations of LiCl do not remove protein A. Only bacteriolytic enzymes can release the protein.Protein A isolated from bacteria after lysozyme digestion contains peptidoglycan constituents. More effective bacteriolytic enzymes such as lysostaphin release peptidoglycan fragments from this protein A preparation.We conclude from these results that protein A is a cell wall component of S. aureus and is covalently linked to the peptidoglycan structure.