摘要:

AbstractCircular dichroism (CD) of solutions of soybean trypsin inhibitor (STI), papain, and an acid mold protease (fromRhizopus chinensis) was determined in the presence and absence of sodium dodecyl sulfate (SDS). The CD bands in the 240–320 nm spectral zone were almost completely eliminated by SDS. This indicated that the tertiary folding was disturbed and the restrictions imposed on the aromatic chromophores were largely removed. The CD bands in the far UV were modified by SDS in a manner that indicated increase of the α‐helix content in these proteins. This specific type of denaturation has been observed also on many other proteins. The termreconstructive denaturationis suggested for this type of denaturation in which the helix content of the polypeptide chain is enhanced by the denaturing a

ISSN:0025-116X    

DOI:10.1002/macp.1972.021580101

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractThe aqueous polymerization of acrylamide initiated by bromate/thiourea redox system has been studied in acidic media at 25 ± 0.2°C in a nitrogen atmosphere.The rate of polymerization has been found to vary with the first power of the potassium bromate concentration within the range 0.75·10−2to 2.0·10−2mole·1−1and nearly with the first power of the hydrochloric acid concentration within the range 2.85·10−2to 8.55·10−2mole·1−1. However, the rate of polymerization is independent of the thiourea concentration, but varies with the first power of the monomer concentration within the range 6.0·10−2to 10.0·10−2mole·1−1. The initial rate increases but the maximum conversion decreases as the temperature increases within the range 19 to 35°C.The over all energy of activation has been found to be 22.9 kcal·mole−1within the temperature range mentioned above. Water miscible organic solvents and mono‐ and dibasic salts show the same effect as given by MISRAet al. The effect of cationic and anionic surfactants has been found to increase and decrease the rate of polymerization (Rp) respectively, however non‐ionic d

ISSN:0025-116X    

DOI:10.1002/macp.1972.021580102

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractThe poly‐L‐lysine/copper(II) complex was found to exhibit the asymmetrically‐selective catalysis on the hydrolysis of phenylalanine esters at pH 7. The reaction rate showed a first order dependence on the ester concentration for the initial part of the hydrolysis. Tetraaquocopper(II) ion and bis(bipyridyl)copper(II) ion had no catalytic activity on the hydrolysis at pH 7. The catalytic activity was discussed on the basis of the stability constant data of these comp

ISSN:0025-116X    

DOI:10.1002/macp.1972.021580103

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractA dilatometer was constructed to study the free radical polymerization kinetics of acrylamide below 0.1Mmonomer. The polymerization was initiated by 4.4′‐azo‐bis‐4‐cyano‐pentanoic acid in aqueous solution at 25°C.The fkdvalue, calculated from dilatometric and viscometric data for a test with initial concentration [M] = 0.093Mand [I] = 2.09·10−3M, was 2.81·10−8sec−1. Comparison with an extrapolated literature value for kdat 25°C indicated an efficiency value, f, equal to 0.65. Both fkdand f were comparable in magnitude to results of other cited investigations.The results of a 3/2 order dependency of polymerization rate on [M] substantiated the apparent tendency of acrylamide concentration exponents to increase above 1.0 below 0.1Mmonomer. A cage effect theory was offered as an explanatio

ISSN:0025-116X    

DOI:10.1002/macp.1972.021580104

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractEpitaxial crystallization of poly‐γ‐benzyl‐L‐glutamate (PBLG) on 001 alkali halide single crystal surfaces results in block and row structures that are qualitatively similar for various solvents and crystals used. There is a definite tendency in the first stages of epitaxial crystallization to align the α‐helical molecules along the 〈110〉 substrate direction. We propose that the epitaxial structures are built up of straight, non‐folded α‐helical molecules associated side‐by‐side and, in the case of low M̄wfractions, also end‐to‐end. The epitaxial crystallization of PBLG was observed only in the vicinity of the precipitation point. The orienting and attracting forces coming from the crystal substrate have a long range character and are of at least two kinds. The decoration effect of PBLG epitaxial structures could be used for substrate surfa

ISSN:0025-116X    

DOI:10.1002/macp.1972.021580105

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractThe conformational state of poly‐L‐glutamic acid (PLGA) in the mixed solvent pyridine/water has been studied by means of different techniques (ORD, IR, PMR, and viscosity). It has been found that at low water contents PLGA forms aggregates the stability of which depends in a sensitive manner on temperature and solvent composition.At higher water content PLGA undergoes a helix–coil trans

ISSN:0025-116X    

DOI:10.1002/macp.1972.021580106

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractDiffusion of helium, oxygen, nitrogen, and carbon dioxide in poly(methyl methacrylate) has been studied. The data are analyzed employing the new modified time‐lag technique developed by PAUL and DIBENEDETTO. Different thermodynamic parameters have been evaluated and the mechanism of gaseous diffusion has been discusse

ISSN:0025-116X    

DOI:10.1002/macp.1972.021580107

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractAus der Winkelabhängigkeit der Lichtstreuung von salzhaltigen DNA‐Lösungen kann auf das Vorliegen von Fernordnungen in der Lösung geschlossen werden. Diese Ordnung bildet sich in den ruhenden Lösungen im Verlauf mehrerer Stunden bis Tage aus. Sie kann durch Rühren gestört werden und verschwindet in der Nähe der Schmelztemperatur der DNA.Aus den gemessenen Extremwerten der Streufunktion läßt sich formal ein BRAGGscher Wert von 6000 Å errechnen, aber auch Periodizitäten von 2000 Å bzw. 3300 Å sind möglich. Zwischen 1 · 10−4bis 3 · 10−4g/ml läßt sich keine eindeutige Abhängigkeit von der Konzentration feststellen, wodurch man hier ein einfaches Parallelstranggitter ausschließen kann. Unmittelbar nach der Filtration durch Flächenfilter der Porenweite 0,5 μm zeigen die DNA‐Moleküle stark g

ISSN:0025-116X    

DOI:10.1002/macp.1972.021580108

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractViskositätsmessungen an Lösungen von Polymethylmethacrylat in Toluol werden nach dem Modell der Netzwerk‐Lösung ausgewertet. Zum Vergleich wird für dasselbe System eine numerische Berechnung der von BUECHE angegebenen Beziehung durchgeführt; es ergibt sich im η0–M‐Verlauf kein Knick, sondern ein Übergang, dessen Breite unter anderem von dem Schlüpffaktor s abhängt. Der Vergleich von Rechnung und Meßdaten ergibt einen vernünftigen Wert des Segment‐Reibungsfaktors f0. Aus den Meßwerten wird weiter das kritische Molekulargewicht Mcermittelt und daraus das scheinbare statistische Fadenelement A′m, das mit Werten aus anderen Messungen befri

ISSN:0025-116X    

DOI:10.1002/macp.1972.021580109

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractEs wurde versucht, die Photolyse von aromatischen Aziden zur Darstellung von Polymeren auszunutzen. Zu diesem Zweck wurden mehrere Bis‐Azide hergestellt und in verschiedenen Lösungsmitteln bestrahlt, wobei die berechnete Menge Stickstoff abgespalten wurde. Die meisten der tiefgefärbten Bestrahlungsprodukte sind unlöslich; bei bestimmten Ausgangsverbindungen konnten in Dichloressigsäure lösliche Anteile erhalten werden. Auf die Struktur der Bestrahlungsprodukte kann durch Vergleich der Spektren dieser Lösungen mit denen einer Modellverbindung geschlossen

ISSN:0025-116X    

DOI:10.1002/macp.1972.021580110

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY