Human Orosomucoid: Dissociation of Tyrosines in the Systems Water-Low Aliphatic Alcohol

1997 ◽  
Vol 62 (10) ◽  
pp. 1533-1543
Author(s):  
Vladimír Karpenko ◽  
Jana Horálková ◽  
Milan Kodíček

The influence of methanol, ethanol, propan-1-ol, and propan-2-ol on the dissociation of tyrosines of human serum orosomucoid (acid α1-glycoprotein) was studied. The content of alcohols was chosen so that their solutions had the same value of the relative permittivity. Then, the contribution of electrostatic effects was equal in all cases and the observed differences between aqueous and alcoholic solutions reflected other, nonelectrostatic effects in the studied systems. Analysis of the spectrophotometric titration curve revealed three kinds of tyrosine groups (n1, n2, n3), but only the values pK1 and pK2 could be calculated. The observed differences of pK values in aqueous and mixed media are discussed and compared with the structural changes of the orosomucoid molecule.

1997 ◽  
Vol 270 (5) ◽  
pp. 739-750 ◽  
Author(s):  
Sandra L Mecklenburg ◽  
Robert J Donohoe ◽  
Glenn A Olah

1991 ◽  
Vol 37 (7) ◽  
pp. 1221-1224 ◽  
Author(s):  
J Merle Sheat ◽  
Robert J Peach ◽  
Peter M George

Abstract We have studied the detection and classification of genetic variants of human serum albumin by electrophoresis. Samples from 10 patients who were heterozygous for eight different albumin variants were studied by two methods. In agarose gel electrophoresis, each of these variants has an abnormal mobility and can be classified on the basis that structural changes at the N-terminus abolish 63Ni binding. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole serum, glycosylated variants are easily detected because of their greater apparent molecular mass.


2008 ◽  
Vol 53 (No. 3) ◽  
pp. 79-84 ◽  
Author(s):  
J. Blahovec ◽  
J. Sobotka

Potato tuber specimens of two varieties (Nicola and Saturna) were deformed in a compression loading/unloading test. The tuber complex permittivity spectrum at frequencies 0.1–500 kHz was measured repeatedly during the deformation. The results show that both parts of relative permittivity (real and imaginary) decrease with increasing deformation and vice versa. The same trend was observed at all studied frequencies even if it was not equally strong in all cases. The permittivity plots versus frequency were similar in both the tested varieties and in different stages of deformation. The influence of tuber deformation on the permittivity values as well as the reversibility of the permittivity changes during the deformation are changed substantially at strains about 20% in comparison to strains up to 10%. The obtained results support the hypothesis that permittivity measurements can serve as an alternative indication of the internal structural changes in potato tissue during its loading.


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