bluuebunny/crossref_metadata_2025_split huggingface dataset:
COMPUTER PROGRAM FOR LOCALIZATION OF DISULFIDE BONDS IN PROTEINS
Authors: Bishop Yvonne M. M. , Katsioules Christine C. , Meienhofer Johannes 
Published: August 2010

A Fortran computer program to aid in disulfide bond analysis in proteins has been developed. The program evaluates amino acid analysis data from isolated cystine‐containing peptides by comparing it with known sequences around pairs of half‐cystine residues in the primary structure of a protein and recording all matches. The method involves presetting upper and lower bounds for each amino acid present in a cystine‐containing peptide by considering both partial degradation during acid hydrolysis and contamination sources for certain amino acids. Initially, limiting path terminals for each half‐cystine residue in the primary structure are determined by examining the surrounding sequences in both directions for “alien” amino acid residues, not present in the composition of a given cystine‐containing peptide. Subsequently, pairwise examination proceeds through several cycles incorporating minimal path and upper bound routines with intermittent revision of path ends. Finally, all pairs of half‐cystines whose surrounding sequences fall within the preset bounds for this peptide are listed. If too many possible pairs or none are found, the bounds are revised. The lists for all available cystine‐containing peptides are graphed to facilitate final determination of disulfide bond positions in the native protein.The computer program provided finite disulfide bond assignments for ovine lactogenic hormone and human growth hormone. In the case of hen egg‐white lysozyme, a considerable reduction was obtained from the large number of theoretically possible disulfide bond combinations to a few alternatives, and one of the four disulfide bonds was unequivocally determined. To assign the positions of the other three disulfide bridges, additional considerations, not included in the program, were applied, such as specificity of the enzymes used in digesting the protein and electrophoretic mobility of the ensuing cystine‐containing peptides
PREPARATION OF CHROMOPHORIC SUBSTRATES FOR THE GLUTAMOYL SPECIFIC STAPHYLOCOCCAL PROTEASE
Authors: Houmard Jean 
Published: August 2010

The synthesis of chromophoric substrates allowing an accurate determination of the staphylococcal protease activity is described. BOC‐L‐Glu‐OPh, BOC‐L‐Phe‐L‐Glu‐OPh, BOC‐L‐Ala‐L‐Glu‐OPh, BOC‐L‐Ser‐L‐Glu‐OPh and Z‐L‐Glu‐pNA were prepared*.Kinetic parameters of the staphylococcal protease‐catalysed hydrolyses of these substrates are compared. In every case the dipeptide ester substrates lead to a lower catalytic efficiency (kcat/Km ratio), compared with either BOC‐L‐Glu‐OPh or Z‐L‐Glu‐OPh, mainly because of an increase in the Km value. Like other serine proteinases, the staphylococcal protease exhibits a high ratio of esterase to peptidase activity, the kcat/Km ratio being 2.6 times 105‐fold higher with the Z‐L‐Glu‐OPh than with the Z‐L‐Glu‐pNA.
IS THE ALKALINE CLEAVAGE OF DISULFIDE BONDS IN PEPTIDES AN α‐β ELIMINATION REACTION OR A HYDROLYSIS?
Authors: FEDERICI GIORGIO , DUPRÈ SILVESTRO , MATARESE ROSA MARINA , SOLINAS SANDRO P. , CAVALLINI DORIANO 
Published: August 2010

The cleavage of oxidized glutathione by alkali has been studied as representative of the cleavage of protein disulfides. This process is quite different when studied in 10‐4 N or 2 ˙ 10‐1 N NaOH. At low alkali concentration no spectral changes are noted; at higher hydroxyl concentration the appearance of persulfide groups (followed at 335 nm), the formation of thiocyanate (arising from cold cyanolysis of persulfide groups) and the absorbance at 240 nm follow the same kinetics. The amount of half‐cystine, recovered as cysteic acid after a 3‐h reaction, is significantly lower than calculated.These results confirm that oxidized glutathione undergoes β‐elimination at high pH values, and that persulfide groups absorb not only at 335 nm (as already known) but also at 240 nm where, under our conditions, the contribution of other absorbing species is not very high.
PRIMARY SPECIFICITY OF ALKALINE MESENTERICOPEPTIDASE
Authors: Stambolieva Nicolina , Chakarova Rumiana 
Published: August 2010

The steady‐state kinetics of the alkaline mesentericopeptidase‐catalysed hydrolysis of esters of the general formula Ac‐X‐OMe(OEt) has been studied, “X” being an amino acid residue (Ala, Val, Leu, Ile, Phe, Tyr, Trp, Lys). The values of the specificity ratio kcat/Km indicate that the bonds involving the carboxyl group of amino acids with aromatic and bulky aliphatic side chain are hydrolysed most effectively. On account of this, alkaline mesentericopeptidase is classified as a chymotrypsin‐like alkaline protease. The primary specificity of mesentericopeptidase reveals the similarity of this enzyme to the group of subtilisins, as well as the distinctive characteristic feature of the enzyme to hydrolyse Ac‐Leu‐OMe with an efficiency practically equal to that of aromatic amino acid derivatives.Suggestions are made about the nature of the substrate‐binding centre, taking into consideration Schechter's and Berger's concepts of the secondary specificity.
PROTEASE B FROM SACCHAROMYCES CEREVISIAE Purification and Characterization
Authors: LOOZE Y. , GILLET L. , DECONINCK M. , COUTEAUX B. , POLASTRO E. , LEONIS J. 
Published: August 2010

Protease B has been isolated from Saccharomyces cerevisiae and purified in six steps as follows: autolysis of the yeast cells, ammonium sulfate fractionation, activation of the proteolytic enzymes, chromatography on DEAE‐cellulose, chromatography on CM‐cellulose and finally, a second chromatography on DEAE‐cellulose.The preparation was shown to be homogeneous on polyacrylamide gels in the absence as well as in the presence of sodium dodecylsulfate. Furthermore, the molecular weight (43 000 daltons) and the isoelectric point (5.45) were in good agreement with earlier published values.The amino acid composition is reported. The absence of disulfide bonds in protease B has to be outlined.The amino acid residues of the protein have been found to be folded nearly quantitatively (at least 80%) in a β‐conformation as deduced from a circular dichroism study.Finally, the tryptophan residues (5 mol/mol protein) are largely buried in the hydrophobic core of the enzyme.
CONFORMATIONAL CALCULATIONS ON GASTRIN C‐TERMINAL TETRAPEPTIDE
Authors: ABILLON ELIANE , van CHUONG PAUL PHAM , FROMAGEOT PIERRE 
Published: August 2010

Energy optimizations were performed on some typical conformations of the gastrin C‐terminal peptide amide NAc‐Trp‐Met‐Asp‐Phe‐NH2. Two families of lowest energy conformations were found corresponding to: (a) α‐helical structures; (b) conformations having β‐structure at the level of Trp residue, and C7‐structure at the level of Asp residue. The two aromatic rings were folded on the peptide backbone and ca. 5 Å distant from each other (centre to centre).The last family, favoured by energy and population probability, can better account for conformational experimental results and biological activity observations.
CARBON 13 NUCLEAR MAGNETIC RESONANCE STUDIES ON FORMALDEHYDE REACTIONS WITH POLYFUNCTIONAL AMINO‐ACIDS
Authors: TOME D. , NAULET N. 
Published: August 2010

Addition and condensation reactions of formaldehyde with poly functional amino‐acids and their Nα‐acetyl derivatives have been studied in neutral or mildly acid solutions using 13C n.m.r.The first addition reaction, giving hydroxymethyls, is fast and incomplete with the amine, guanidyl, hydroxyl, indole and imidazole groups of the side chains, fast and complete with the sulfhydryl group, slow and complete with the amide group.For asparagine, threonine, histidine and tryptophan, the Nα‐hydroxymethyl condenses with the basic group of the side chain to give a cyclic compound. In the case of cysteine, it is the S‐hydroxymethyl which condenses with the α‐amino group.The value of the chemical shifts of the hydroxymethyls and of the methylene bondings will be of help in the study of the reactions of formaldehyde with proteins.
Amino acid sequence of the small cyanogen bromide peptide of thermitase, a thermostable serine proteinase from Thermoactinomyces vulgaris
Authors: BAUDYŠ M. , KOSTKA V. , GRÜNER K. , HAUSDORF G. , HÖHNE W.E. 
Published: August 2010

The following amino acid sequence of the small cyanogen bromide peptide (mol. wt. 5399) of thermitase from Thermoactinomyces vulgaris has been determined: Ala‐Thr‐Pro‐His‐Val‐Ala‐Gly‐Val‐Ala‐Gly‐Leu‐Leu‐Ala‐Ser‐Gln‐Gly‐Arg‐Ser‐Ala‐Ser‐Asn‐Ile‐Arg‐Ala‐Ala‐Ile‐Glu‐Asn‐Thr‐Ala‐Asp‐Lys‐Ile‐Ser‐Gly‐Thr‐Gly‐Thr‐Tyr‐Trp‐Ala‐Lys‐Gly‐Arg‐Val‐Asn‐Ala‐Tyr‐Lys‐Ala‐Val‐Gln‐Tyr.The results obtained support the classification of the enzyme as a serine proteinase of the subtilisin type as proposed in a previous paper (1). This partial sequence extending from the serine residue involved in the active site to the C‐terminal amino acid of the enzyme shows a 40% homology with the corresponding part of the subtilisin BPN' or subtilisin Carlsberg molecule but a 56% homology as regards conservative amino acid replacements.The secondary structure of this polypeptide fragment, predicted from the data obtained by the method of Chou & Fasman (2) agrees fairly well, within the limit of error of the method, with the structure of the corresponding part of the subtilisin BPN' molecule. Therefore, as expected, no dramatic changes in the spatial structure appear to account for the higher thermostability of thermitase, at least in this area of the polypeptide chain.
Physalaemin‐like immunoreactive peptides from rabbit stomach
Authors: WILSON W.E. , HARVAN D.J. , HAMM C. , LAZARUS L.H. , KLAPPER D.G. , YAJIMA H. , HAYASHI Y. 
Published: August 2010

Two physalaemin (PHY)‐like immunoreactive peptides, designated PHLIPs, have been purified from extracts of rabbit stomach tissue. Fast atom bombardment/ mass spectrometry (FAB/MS) indicated that the m/z values for the PHLIP pr‐tonated molecular ions were 867.419 and 796.4. FAB/tandem MS spectra, coupled with a knowledge of the amino acid composition and the aid of a computerized fragment‐matching program, indicated the amino acid sequences to be:< Glu‐Val‐Asp‐Pro‐Asn‐Ile‐Gln‐Ala PHLIP‐8, and< Glu‐Val‐Asp‐Pro‐Asn‐Ile‐Gln PHLIP‐7The sequences of PHLIPs‐7 and ‐8 were confirmed with synthetic peptides. The PHY‐antiserum cross‐reactivity of the PHLIPs reflects homology at amino acid residues 1, 3, 4 and 5 for the mammalian and amphibian residues.
H‐Gly‐Hisψ(NHCO)Lys‐OH, partially modified retro‐inverso analogue of the growth factor glycyl‐L‐histidyl‐L‐lysine with enhanced enzymatic stability
Authors: DALPOZZO ALMA , KANAI KAROLY , KERESZTURI GÉZA , CALABRESE GERARDO 
Published: August 2010

A partially retro‐inverso analogue of the natural growth factor GHK was synthesized, in which the —CONH— bond between histidine and lysine was modified as —NHCO—. This modification is not expected to perturb the spatial distribution of the side‐chains, and therefore the binding processes, compared to the native peptide.In the synthesis of the analogue two possible systems for deblocking of Nπ‐Born group of histidine have been applied and compared. An alternative method is also described for the incorporation of malonyllysine into the peptide chain.When evaluated with respect to resistance toward degradation by human plasma in vitro, the new peptide analogue showed approximately a ten‐fold increase in stability versus the parent peptide.
Cyclic analogues of wasp kinins from Vespa analis and Vespa tropica
Authors: GOBBO MARINA , BIONDI LAURA , FILIRA FERNANDO , ROCCHI RANIERO , PIEK TOM 
Published: August 2010

Syntheses are described of two bradykinin‐like kinins isolated from Vespa analis (G‐R‐P‐P‐G‐F‐S‐P‐F‐R‐V‐I, VSK‐A) and Vespa tropica (G‐R‐P‐Hyp‐G‐F‐S‐P‐F‐R‐V‐V, VSK‐T) and of their cyclic analogues. Linear dodecapeptides were prepared by the solid‐phase procedure based on Fmoc‐chemistry, and cyclization was carried out by the diphenyl‐phosphorazide method.Peptides were characterized by amino acid analysis, optical rotation, analytical HPLC and FAB‐MS. The conformational features of the cyclic and linear kinins were determined by circular dichroism measurements in water, 95% trifluoroethanol and 8 M guanidinium chloride. Consistent with previous findings, preliminary pharmacological experiments on smooth muscle preparations showed that cyclic wasp kinins were 50–100 times less potent than their linear analogues. Moreover, cyclo‐VSK‐A and cyclo‐VSK‐T behave like kininase inhibitors by preventing the degradation of straight kinins.
Kinetic study of racemization of aspartyl residues in model peptides of αA‐crystallin
Authors: FUJII NORIKO , MOMOSE YUKO , HARADA KAORU 
Published: August 2010

We have reported that two aspartyl (Asp‐151 and Asp‐58) residues in αA‐crystallin in human eye lens were inverted to the D‐isomer and isomerized to β‐aspartyl residues with age.We report here the kinetics of the Asp racemization of three model peptides corresponding to fragments of αA‐crystallin: IQTGLD151ATHAER (T18 peptide). TVLD58SGISEVR (T6 peptide) and HFSPED84LTVK (T10 peptide, as a control). The rate constants of the racemization of Asp residues in these peptides were measured at pH 7.0. at five temperatures: 50, 60, 70, 80 and 90 °C. From the Arrhenius equation, we estimated the activation energy (E) of racemization and the time required for the Asp D/L ratio to approximate to 1.0 (D/L ratio of Asp = 0.99) at body temperature. For the peptide T18, E=21.4 kcal/mol and t=13.5 yr. For the peptide T6, E= 26.8 kcal/mol and t= 49.5 yr. For the control peptide T10, E=28.3 kcal/mol and t= 78.1 yr. The racemization rate of Asp in these three peptides is parallel to that of Asp residues in αA‐crystallin. The racemization rate of Asp in the T18 peptide was very rapid compared to that in the other peptides. This result also reflects the racemization rate in native αA‐crystallin
Solid‐phase synthesis of peptide‐4‐nitroanilides
Authors: KASPARI ANNE , SCHIERHORN ANGELIKA , SCHUTKOWSKI MIKE 
Published: August 2010

A wide variety of Glu/Asp and Gln containing peptide‐4‐nitroanilides and other chromogenic peptidyl‐arylamides could be quickly synthesized by a Fmoc‐based solid‐phase synthesis strategy employing the side‐chain carboxyl groups for transient anchoring to the resin. Suitable synthons for this method, Fmoc‐Glu‐NH‐Np and Fmoc‐Asp‐NH‐Np. were prepared using a diphenylphosphinic chloride‐mediated coupling reaction. Peptides of the common structure Suc‐Ala‐Phe‐Pro‐Xaa‐NH‐Np (Xaa = Glu/Asp, Gln) were synthesized and were shown to be substrates for the protease subtilisin Carlsberg (E.C.3,4,21,14a) and for peptidyl‐prolyl cis/trans‐isomerases (PPIases E.C.5,2,1,8,). The method was extended to amino acids possessing a side chain missing an anchor for binding to the matrix. We synthesized Suc‐Ala‐Phe‐Pro‐Gln‐Phe‐NH‐Np anchoring the dipeptide derivative Fmoc‐Glu‐Phe‐NH‐Np with the carboxyl group to Rink amide resin using standard SPPS procedures. Additionally this procedure allowed us the preparation of peptidyl‐arylamides, utilizing the commercial available Fmoc‐Glu‐OAll as building block.A mixture of pentapeptide‐4‐nitroanilides with the general sequence Ala‐Ala‐Xaa‐Pro‐Gln‐NH‐Np was synthesized. Electrospray ionization mass spectrometry (ESI‐MS) was used to evaluate the hydrolysis of the peptide mixture by the protease subtilisin Carlsberg. It could be shown that peptides with the hydrophobic amino acids Phe. Tyr, Leu and Val in the varied P3‐position were most rapidly cleaved under the chosen conditions. Hydrolysis of the Gln‐NH‐Np bond in Ala‐Ala‐Pro‐Pro‐Gln‐NH‐Np has not been observed. © Munksgaard 1996.
Kaliumjodatzusatz (KJO3) zu Viehsalz zwecks Erhöhung des Jodgehalts der Kuhmilch
Authors: Németh Š. 
Published: August 2010

ZusammenfassungFünftägige Verfütterung von täglich 50 g Viehsalz mit Zusatz von 26 mg Kaliumjodat (KJO3) erhöhte den Jodgehalt der Kuhmilch durchschnittlich um 80 μg pro Liter Milch. Die Hälfte dieser Dosis sicherte den halben Effekt.Im Vergleich mit den entsprechenden Jodidmengen scheint das Jodat in dieser Hin‐sicht eine etwas stärkere Wirkung zu haben.
Untersuchungen über den Einfluß von Antibiotica auf den respiratorischen Stoffwechsel des Schweines1
Authors: Hörnicke H. 
Published: August 2010

ZusammenfassungEs wurden Respirationsversuche durchgeführt, um den Einfluß von Antibiotica auf die Kalorienproduktion und den respiratorischen Quotienten von Schweinen im Gewicht von 20 bis 30 kg zu prüfen. Einmalige Eingaben von 100 mg Aureomycin an nüchterne Tiere waren ohne Einfluß auf den respiratorischen Quotienten. In der ersten Woche nach der Zufütterung von Aureomycin an ein bisher ohne Zusätze aufgezogenes Tier war keine Verschiebung des RQ zu erkennen, jedoch kam es zu einer Vorverlegung und Vergrößerung des Maximums der motorischen Aktivität. Durch Verfütterung von Aurofac an eiweißmangelernährte Schweine wurde der respiratorische Quotient sta‐tistisch signifikant gesenkt, was als eine Verminderung des durch den Eiweißmangel ge‐steigerten Fettansatzes gedeutet wird.
Ist die Weidetetanie eine Nitratvergiftung?
Authors: Rathje Werner 
Published: August 2010

ZusammenfassungProben von Weidelgras von Weiden, die Tetanie erzeugen und frei von Tetanie sind, zeigten ksine Unterschiede im Nitratgehalt. Lediglich Proben von nur zwei Weiden, auf denen Tetanie stark auftrat, wiesen einen bedeutend höheren Nitratgehalt auf. Da es nicht statthaft ist, von diesen wenigen Proben zu schließen, daß die Weidetetanie eine Nitratvergiftung darstellt, soll dieser Befund so lange fraglich bleiben, bis er von anderer Seite bestätigt wurde.Einige Hinweise aus der Literatur deuten auf die Möglichkeit hin, die Weidetetanie als Nitratvergiftung anzusehen.
Beitrag zu den parameterfreien Testmethoden in der Biostatistik
Authors: Müller‐Settele A. 
Published: August 2010

ZusammenfassungIn vorliegender Arbeit wurde auf die immer größer werdende Bedeutung der Statistik für alle Gebiete der experimentellen Naturwissenschaften hingewiesen. Da man bei biostatischen Analysen von Versuchsergebnissen des öfteren auf Verteilungsformen stößt, für die die Annahme einer normalen Verteilung nicht zulässig ist, ist es besser, um Fehlentscheidungen zu vermeiden, verteilungsfreie Testmethoden anzuwenden.Zwei der wichtigsten parameterfreien Testmethoden, der Zeichentest und der Wilcoxon‐Test, wurden theoretisch kurz erläutert und es wurde an praktischen Bei‐spielen ihre Durchführung gezeigt.
Zum Wachstum bei Muttermilch und Muttermilchersatz
Authors: Lenkeit W. , Freese H. H. 
Published: August 2010

ZusammenfassungEs wird eine vorläufige Mitteilung gegeben über Stoffwechseluntersuchungen an säu‐genden Ferkeln bei Zufuhr von Muttermilch und Muttermilch‐Ersatz. Nach bisherigen Untersuchungen können säugende Ferkel mit geeigneten Milch‐Ersatz‐Mischungen mehr an N, an Ca, Mg und P ansetzen als bei maximaler Muttermilchnahrung. Als günstiges Verhältnis der Protein‐ zur Gesamtenergie wurde 1:3 gefunden, gegenüber 1:4 in der Muttermilch.
Untersuchung des Leberkreislaufs an Schafen
Authors: Juhász B. , Gertner M. , Szegedi B. 
Published: August 2010

ZusammenfassungDie durch die Leber strömende gesamte Blutmenge wurde mit dem Bromsulfalein‐Ver‐fahren (Werner und Horváth; J. Clin. Invest., 31, 433, 1952) an urethan‐chloralose‐narkotisierten Schafen bestimmt. Das Verfahren erfordert aus der V. hepatica stam‐mendes Blut, das mit Hilfe des unter Röntgenkontrolle durch die V. jugularis einge‐führten sog. Herzkatheters gewonnen wurde. Die Errechnung der durch die Leber strö‐menden gesamten Blutmenge erfolgte aus der Differenz der Bromsulfalein‐Konzentra‐tion des arteriellen und V. hepatica‐Blutplasmas und aus der durch Infusion verab‐reichten Bromsulfaleinmenge mit Hilfe des Hämatokrits. Außerdem wurde in den letzten Versuchsperioden Blut aus der V. portae entnommen und in diesem ebenso wie im Blut der V. hepatica, V. jugularis und A. femoralis der Ammoniakgehalt nach dem Verfahren von Juhász und Szegedi (Acta Vet. Hung., 1, 81, 1958) bestimmt. Die Ver‐suche ergaben folgende Resultate:Die durch die Leber strömende gesamte Blutmenge beträgt im Mittelwert 1026 ml/min (589 bis 1433).Je 1 kg Körpergewicht macht die Blutmenge im Mittelwert 26,4 ml/min (17,2 bis 28, 4) aus.Auf 100 g Leber berechnet entspricht die Blutdurchströmung im Mittelwert 165,1 ml/min (116,5 bis 228,5).Der Mittelwert der Bromsulfalein‐Extraktion ist 24,9 %. Die gesamte durch die Leber strömende Blutmenge macht etwa 16 % des Herzminutenvolumens aus. Es wurde ferner festgestellt, daß 26 % des gesamten Leberkreislaufs aus Pansen und Netzmagen stammen.Die von verschiedenen Gefäßgebieten entnommenen Blutproben zeigten im Mittelwert folgende Ammoniakkonzentrationen: V. portae 529 μg% (360 bis 680), V. jugularis 131 μg%, V. hepatica 114 μg%.Aus diesen Angaben wurde errechnet, daß die Leber binnen 24 Stunden 7,82 g Ammoniak aufnimmt.Bei hungernden Tieren hält die Leber etwa 80 % des Ammoniakgehalts im Blut der V. portae zurück und überläßt den Rest der V. hepatica.
Grundstandard als Sauen‐ und Ferkelf utter1
Authors: Andreae U. 
Published: August 2010

ZusammenfassungZusammenfassend ist daher festzustellen, daß die sogenannte Grundstandardmischung nicht nur als Kraftfutter für säugende Sauen zu verwenden ist, sondern sich gleichzeitig auch gut als Beifutter für Saugferkel eignet.Im Preis je 1000 StE weichen Vergleichsmischungen und Grundstandardmischung nur unerheblich voneinander ab. Infolgedessen ist auch vom wirtschaftlichen Standpunkt aus die Verwendung von Grundstandardschrot gerechtfertigt, insbesondere dann, wenn man den 50% igen Anteil an Gerstenschrot, wie es in diesem Falle geschehen ist, aus dem wirtschaftseigenen Vorrat entnehmen und zum Ab‐Hof‐Preis einsetzen kann.
Eine vielseitige Diätform für Ratten (Zugleich ein Beitrag zur Stoffwechselmethodik)
Authors: Horn V. , Eder H. , Wels A. 
Published: August 2010

ZusammenfassungEs wird über eine Diätform für Ratten berichtet, die sich bei Wachstums‐, Vitamin ‐und Stoffwechselversuchen bewährt hat.Ferner werden Vorschläge zur Verbesserung der Stoffwechselmethodik gemacht.