E. V. Korolik

Effect of the conditions of isolation on the physicochemical properties of human serum albumin in the norm and with pathology

Differential scanning calorimetry and IR spectrosocopy were used to investigate the effect of the procedure of isolation of human serum albumin on its physicochemical characteristics. It is shown that fractionation of blood plasma with ethylene glycol followed by ion exchange chromatography can be used to obtain albumin of normal donors that is similar to the albumin in the nonfractionated plasma according to melting thermograms. Endotherms of human serum albumin samples that were obtained by affinity chromatography and preparative electrophoresis are bimodal, unlike the monophasic for albumin obtained by polyethylene glycol precipitation. These changes result from a higher content of nonetherified fatty acids in the albumin samples obtained by affinity chromatography and from modification of the secondary protein structure in the samples obtained by electrophoresis. Analysis of melting thermograms of serum albumin from patients with uremia, chronic hepatitis, and peritonitis shows that fractionation of blood with polyethylene glycol preserves the thermodynamic characteristics of the various pathological serum albumins to the greatest extent. The present results demonstrate the advantage of polyethylene glycol fractionation for isolation of native preparations of normal and “pathological” human serum albumin.

IR and Raman spectroscopic investigation of the globular package of the human serum albumin at pmnjhuy76athology

Human serum albumin (HSA) is the most important carrier of organic anions in the humoral mediums of the organism. As distinguished from other transport proteins selectively interacting with a definite class of ligands HSA can affiningly combine with compounds different in their chemical nature, such as fatty and biliary acids, bilirubin, steroid and thyroid hormones and many medicinal substances. This is possible, because in the HSA molecule there exist conformationally labile regions capable of adaptation to different chemical groups, when interaction with ligands, and formation of a high-affining combining centre. An intense ligand loading of albumin molecules causes changes in their structure and combining capacity. The molecular mechanism of the ligand-induced conformation of HSA is not clearly understood, particularly, the problem on the character of the structural changes in protein in the case of different pathological states remains unsolved.

Vibrational spectra of the products of interaction of enzymes with a monocarboxylcellulose matrix

By the method of IR spectroscopy it is established that the process of sorption of celiase, trypsin, chymotrypsin, streptase, plasminogen, and plasmin by monocarboxylcellulose (the content of COOH groups is 15 wt.%) is mainly identical. The determining role in the mechanism of binding of monocarboxylcellulose with the considered medicinal enzymes belongs to electrostatic interactions with the formation of ionic bonds between the COO− groups of the matrix and charged amine groups of protein molecules. It is established that the process of interaction of plasmin with oxidized cellulose takes a more active course than with other investigated enzymes. It is shown that the activity of interaction of the enzymes with monocarboxylcellulose can be evaluated by a change in the relative intensity of the band of stretching vibrations of C=O groups.