摘要:

AbstractKerr constants and birefringence relaxation times were measured on gamma‐globulin (I) in aqueous solution and on bovine serum albumin (II), beta‐lactoglobulin (III), ovalbumin, (IV), ribonuclease (V), lysozyme (VI), and chymotrypsin (VII) in glycerol–water solutions. Rotational diffusion constants were calculated from the data and were compared with those calculated from the protein dimensions obtained by other methods. The calculated and observed rotational diffusion constants were in excellent agreement for I, IV, V, and VII, and were within a factor of two for III. VI showed evidence of aggregation and II gave a low relaxation time in glycerol–water solution, apparently because of a structural change or a localized solvent viscosity effect. The earlier results for maximum dimensions based upon the dielectric relaxation time method were found to be in agreement with present findings in a number of instances, in spite of the possible complication of the dielectric method by ionic polarization

ISSN:0006-3525    

DOI:10.1002/bip.360010602

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1963

数据来源: WILEY

摘要:

AbstractFree poly‐L‐lysine base has been synthesized from ϵ,N‐trifluoroacetyl‐α,N‐carboxy‐L‐lysine anhydride via poly‐ϵ,N‐trifluoroacetyl‐L‐lysine (IV). No racemization occurred during the removal of trifluoroacetyl groups from IV with 1Mpiperidine. Measurements of optical rotatory dispersion suggest that IV exists in methanol in a helical form. The synthesis of poly‐L‐lysyl rabbit ser

ISSN:0006-3525    

DOI:10.1002/bip.360010603

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1963

数据来源: WILEY

摘要:

AbstractIt has been suggested previously that water is a nearly indifferent solvent for amylose on the basis that the exponentaof the Mark‐Houwink equation is very nearly 0.50 and the second virial coefficientA2is extremely small. It is shown that such solutions do not show the expected precipitation on cooling and the temperature coefficient of the intrinsic viscosity is small and negative. It is suggested that water is both an indifferent and a nearly athermal solvent for this polymer. Various lines of evidence suggest the polymer to exist as a very stiff coil in this and in other solvents. Variations in the intrinsic viscosity and radius of gyration in various solvents show the importance of skeletal effects in addition to the usual osmotic effects. Application of the Porod‐Kratky wormlike coil model leads to unreasonably short persistence lengths if the contour length is based on a fully extended conformation but large and reasonable values of the order 40–70 A. if it is assumed that the basic conformation is the helical one observed in various amylose complexes in the crystalline state. As was previously known, the specific optical rotation decreases sharply in aqueous solutions above approximately pH 12. Accompanying this change in rotation there is first a decrease, then an increase in intrinsic viscosity. This later behavior is strikingly reminiscent of the known behavior of polyglutamic acid in the pH‐dependent transition from helix to coil. It is concluded that the conformation is that of a stiff coil with essentially helical backbone contour in neutral solution, and the decrease in rotation and in intrinsic viscosity at high pH results from a partial breakdown of the helical structure with a concomitant increase in backbone flexibility. The increase in viscosity and radius of gyration in extreme alkaline solution is probably due to a polyelectrolyte expansion of the polymer coil. Some other miscellaneous observations which are in accord with this model are also poin

ISSN:0006-3525    

DOI:10.1002/bip.360010604

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1963

数据来源: WILEY

摘要:

AbstractPoly‐β‐hydroxybutyric acid has been isolated from two bacterial sources by two different procedures. Molecular weight and intrinsic viscosity for the two samples were vastly different. This was blamed on degradation occurring during polymer isolation. An optical rotatory dispersion curve for the high molecular weight sample showed a sharp increase in specific rotation at wavelengths less than 450mμ. From this fact and the reported optical activity of the monomer it is concluded that the polymer is stereo‐regular. X‐ray examination of the “native” and “regenerated” polymer yielded the same crystalline pattern. Electron diffraction and x‐ray data on single crystals of the polymer indicate a fiber repeat of 5.9 A. The value can only be reconciled with some kind of helical conformation

ISSN:0006-3525    

DOI:10.1002/bip.360010605

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1963

数据来源: WILEY

摘要:

AbstractData are presented for electric conduction in solid sodium deoxyribonucleate as a function of water content and over a wide range of frequencies. We have also examined the loops seen in a ferroelectric hysteresis bridge. It is proposed that both the conductivity and the loops of samples with high water content are probably due to ion conduction and electrolysis. Dry samples appear to have the characteristics of an inhomogeneous semiconductor. Possible mechanisms of carrier generation are briefly discussed.

ISSN:0006-3525    

DOI:10.1002/bip.360010606

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1963

数据来源: WILEY

摘要:

AbstractAn oriented film of γ‐globulin fibrils obtained by precipitating human γ‐globulin with anti‐human γ‐globulin horse serum was examined with polarized infrared light. When the film was examined with light polarized parallel to the fibril axis, the amide I band was observed at 1635 cm.−1, indicating the cross‐β structure in γ‐globulin fibrils. The reasonableness of this structure for γ‐globulin is discussed by comparing its optical rotatory dispersion constants with those of poly‐O‐acetyl‐L‐serine, which had previously been shown to be the

ISSN:0006-3525    

DOI:10.1002/bip.360010607

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1963

数据来源: WILEY

ISSN:0006-3525    

DOI:10.1002/bip.360010608

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1963

数据来源: WILEY

ISSN:0006-3525    

DOI:10.1002/bip.360010610

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1963

数据来源: WILEY

ISSN:0006-3525    

DOI:10.1002/bip.360010601

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1963

数据来源: WILEY