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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Diabetologia 4 (1968), S. 118-122 
    ISSN: 1432-0428
    Keywords: Beef insulin ; reduced insulin-A-chain ; partially oxidized insulin-A-chain ; reduced insulin-B-chain ; A-chain oligomers ; B-chain polymers ; thiol-disulphide interchange ; thiol groups ; reduction ; stability ; inactivation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Quand l'insuline réagit avec la chaîne B bithiol (préparée à partir de l'insuline de boeuf) dans un rapport molaire 1∶1, à pH 9.5, en présence ou en l'absence d'oxygène de l'air, il se forme des chaînes oligomères et polymères reliées par des liaisons disulfure. — Des quantités équimolaires de chaîne-A d'insuline, sous sa forme tetrathiol, provoquent également une transformation partielle de l'insuline en produits oligomères et polymères, quand elles sont mises en réaction avec l'insuline à pH 9.3, en présence d'oxygène de l'air. Cependant, la chaîne A partiellement oxydée, contenant en moyenne 2 moles de groupement SH par mole de chaîne A, n'attaque pas l'insuline dans ces conditions de réaction.
    Abstract: Zusammenfassung Aus Rinderinsulin isolierte B-Kette in der Bisthiolform reagiert mit Insulin bei der Umsetzung im Molverhältnis 1∶1 und pH 9.5 sowohl in Gegenwart als auch bei Ausschluß von Luftsauerstoff unter Bildung von oligomeren und polymeren über Disulfidbindungen verbundenen Ketten. — Auch Insulin-A-Kette in der Tetrathiolform wandelt Insulin bei pH 9.3 in Gegenwart von Luftsauerstoff teilweise in oligomere und polymere Produkte um, wenn äquimolare Mengen in die Reaktion eingesetzt werden. Unter gleichen Reaktionsbedingungen greift partiell oxydierte A-Kette, die durchschnittlich 2 Mole SH-Gruppen pro Mol Kette enthält, Insulin nicht an.
    Notes: Summary When insulin is reacted with bis-thiol-B-chain (prepared from beef insulin) in a molar ratio 1∶1 at pH 9.5 in the presence or absence of air, oligomeric and polymeric chains, linked by disulfide bonds, are formed. Equimolar amounts of insulin-A-chain in its tetrathiol form when brought into reaction with insulin at pH 9.3 in the presence of air also cause a partial transformation of insulin into oligomeric and polymeric products. Partially oxidized A-chain, however, containing an average of 2 moles SH-groups per mole of A-chain, does not attack insulin under these reaction conditions.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    International journal of cosmetic science 9 (1987), S. 0 
    ISSN: 1468-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The aim of this research is to study the in vitro interaction of the anionic surfactant sodium dodecyl sulphate with human heel callus with special regard to the callus proteins.The sorption of SDS by callus is analysed at different pH values, demonstrating the expected maximum binding of the anionic surfactant at low pH. In both surfactant and blank solutions, swelling of the callus pieces occurs but to different extents. The sorption of SDS by callus is accompanied by a loss of free amino acids and proteins. The protein composition of the callus residues after chemical treatment and of the corresponding treatment baths is examined by amino acid analysis and shows differences in the respective molar amino acid ratios. Results obtained with more specific techniques, such as gel electrophoresis and immunoblotting, demonstrate identical as well as different protein components in the treatment baths depending on the experimental conditions (pH, blank or SDS). Although effects due to the surfactant treatment are in principle more distinct than with blank experiments, those of the latter cannot be neglected.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    International journal of cosmetic science 11 (1989), S. 0 
    ISSN: 1468-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The influence of permanent waving on hair proteins was studied in order to obtain additional information about the chemistry of this cosmetic treatment. It was shown by amino acid analysis that with increasing reduction time during treatment fewer disulphide bonds were reformed in hair during subsequent reoxidation. Simultaneously, an increasing amount of sulphur-containing material is liberated from the hair, as demonstrated by the sulphur balance calculated from the sulphur-containing amino acids. The amount liberated is increased when an extensive soaking of the samples in water between the reduction and reoxidation step is performed. Comparing treatments with the use of reducing solutions of pH values between 7.5 and 10.0, it was found that the largest amount of cystine cleavage occurs at pH 9.0. All hair samples reduced at pH values above pH 8.5 showed incomplete reformation of the disulphide bonds during subsequent reoxidation. This was indicated by the content of free SH-groups and cysteic acid, as quantified by amino acid analysis. The damage to the hair proteins due to permanent waving was further confirmed by the determination of the pronase solubility. The reductive treatment of hair at pH 7.5 led to a relatively low degree of reduction, however all sulphur bonds were reformed during subsequent reoxidation.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    International journal of cosmetic science 9 (1987), S. 0 
    ISSN: 1468-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Amino acid analysis, photometry and polarography were selected as analytical methods for the determination of thiol and disulphide groups in untreated human hair and the results are discussed. The pre-treatments necessary for the different analytical methods, e.g., hydrolysis, to some extent already induce chemical changes of the cysteine and cystine derivatives leading to method-dependent differences in the results. In many cases the partial oxidation products of cystine are supposed to be responsible for this effect. Electron Spectroscopy for Chemical Analysis (ESCA), as an analytical method for the determination of the cystine oxides, was found to be inapplicable due to insufficient resolution and sensitivity, whereas by the use of Fourier Transform Infrared (FTIR) Spectroscopy the sulphur-oxygen vibrations could be analysed and cystine monoxide and cystine dioxide were detected.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Industrial and engineering chemistry 19 (1980), S. 496-501 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 262 (1984), S. 839-840 
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 88 (1957), S. 646-651 
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Zusammenfassung Beim Azidieren von Carbobenzoxy-l-tyrosyl-glycin-hydrazid mit überschüssigem Nitrit wird der Phenolkern des eingebauten Tyrosins nitriert und bei der Reaktion des nitrierten Azids mitdl-Alanin-benzylester das Nitropeptidderivat erhalten.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Naturwissenschaften 54 (1967), S. 396-402 
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 98 (1967), S. 745-754 
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 197 (1964), S. 14-26 
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Zusammenfassung Die aus der Chemie der löslichen Proteine gewonnenen Erkenntnisse über hydrophobe Wechselwirkungen als Faktor der Konformations-Stabilisierung werden auf die Faserproteine Kollagen und Keratin angewandt. Kriterium der Untersuchung ist in erster Linie die Beeinflussung einiger Verhaltensweisen der Faserproteine bzw. reaktiver Proteingruppen durch den Übergang von Wasser zu Wasser-Alkohol-Gemischen als Reaktionsmedium. Dehnungs- und Relaxationsuntersuchungen zeigen eine mit steigender Kettenlänge der Alkohole zunehmende Schwächung von Wollfasern. Der Effekt nimmt mit der Alkoholkonzentration zu und erreicht im mittleren Konzentrationsbereich ein Maximum; bei weiter steigender Alkoholkonzentration werden die Fasern durch Entwässerung wieder stabilisiert. Durch Messen der Schrumpfungstemperatur wird ein gleichartiges Verhalten von Sehnenkollagen festgestellt. Auch die Geschwindigkeit und das Ausmaß der Carboxymethylierung von Thiolgruppen in reduzierter Wolle wird durch die Kettenlänge des Alkohols beeinflußt, wird also durch die Aufspaltung hydrophober Faserbereiche begünstigt. Der Sodaabbau von Wollcystin verläuft zwar in Wasser-Alkohol-Gemischen ebenfalls beschleunigt, doch ist die Kettenlänge ohne Einfluß. Für diese Fälle wird eine Veränderung des angreifenden Agens durch den Alkohol, z. B. durch Störung der Solvathülle, diskutiert. Die Gegenwart von Natriumdodecylsulfat erhöht die Stabilität des Keratins gegen Abbaureaktionen. Diese Beobachtung wird als Verstärkung des hydrophoben Charakters der Wolle durch Addition des anionischen Netzmittels an kationische Proteingruppen gedeutet.
    Type of Medium: Electronic Resource
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