[Complex formation of copolymers of 4-vinylpyridine and 4-vinyl-cetylpyridinium bromide with serum albumin].
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Biomedical subjects
Publications and source records attributed to M I Mustafaev.
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Immunogenicity of soluble protein antigens in the complexes with synthetic polyions may be regarded as depending both on the nature of polymer carrier and the structure of the protein-polyelectrolyte complex. The immunogenicity of stable soluble complexes of ovalbumin (OA) with polycation - quaternized poly-4-vinylpyridine (C-1) and copolymer of acrylic acid and 2-methyl-5-vinylpyridine (C-2) have been evaluated. Immunization of mice by C-1 have induced a vigorous formation of the anti-OA IgG antibodies and IgE homocytotropic antibodies, while immunogenicity of OA in C-2 was comparable with that of OA alone. The analysis of the structural-chemical features of the complexes investigated has shown that enhanced immunogenicity of C-1 may be due to (1) the non-homogeneous distribution of protein globulae among polycation macromolecules and to (2) the formation of complex with an asymmetrical structure, to (3) the high ability of C-1 to adsorb on a surface of the lymphoid cells and to induce a formation of intercellular aggregates. An enhancing of a stability and a size of C-2 in the presence of Cu2+ shows no influence on a immunogenicity of OA. An immunogenicity of both types of complexes does not depend upon the access of determinants of OA to antibodies so far as it has been shown that complex formation in both cases are not accompanied by an alteration of antigenicity and allergenicity of OA.
Interaction of bovine serum albumin (BSA) with quaternized poly-4-vinyl pyridine (PE) in aqueous solutions at pH 7 was studied. It was shown that in a wide range of the ratios of the components (nBSA/nPE) soluble stable cooperative complexes were formed. At the same time a certain critical content of the protein exists at which the system loses its homogeneity. Complex formation is not accompanied by protein denaturation. At smaller nBSA/nPE ratios non-homogeneous distribution of protein globulas among polyelectrolite macromolecules was found; this corresponded to the "all or none" principle. Using ultracentrifugation technique viscosimetric measurements and electron microscopy it was shown that the soluble complexes exist in the form of rode-like particles consisting of protein globules stabilized by polycation chains. Such particle can be considered as a model of nucleoprotein complex. At certain crytical nBSA/nPE rations the rod-like particles aggregate with additional number of BSA-molecules and form more complicate soluble and insoluble cooperative complexes. Possible structural models of the complexes described were suggested and the thermodinamic and kinetic cryteria of their self-assembly were discussed.
It has been shown by high-velocity sedimentation that BSA forms soluble complexes with polyacrylic acid (PAA) and sodium polystyrene sulfonate (PSSNa) with neutral water solutions. Factors responsible for polyanion binding of similarly charged BSA molecules are analysed. It has been found that occupation of PAA and PSSNa chains with BSA globules proceeds steadily. BSA-PAA and BSA-PSSNa complexes are compared with the earlier described products of BSA sorption on poly-4-vinyl-N-ethylpyridine bromide, where the occupation of polycations with protein globules proceeds unevenly. Reasons for the existence of two types of soluble BSA-polyelectrolyte complexes are described; probable structural model of BSA complex with polyacids and polyanions is suggested.
Mechanism of heparin interaction with the soluble complexes polyacrylamide (PA)--protein fractions of the whole serum has been examined. Addition of heparin to a mixture of the soluble complexes serum proteins (SP)--PA gives rise to the macromolecular reaction of protein replacement by negatively charged polysaccharide (heparin) according to the following scheme: (PA)--SP complex) plus heparin in equilibrium or formed from (PA--heparin complex) pus SP. Succession has been studied of heparin removal of different proteins from their polycation-including soluble complexes.
Interaction of bonive serum albumin with copolymers 2-methyl-5-vinylpyridine, acrylic and methacrylic acids in different proportions in aqueous solutions was studied. It was shown, that in a wide range of ration of the components soluble cooperative complexes were formed. Ability of amphotheric copolymers to form complexes with bovine serum albumin depend both on the composition of the copolymers and on the pH of the medium. The non-polar interactions of the protein globules with hydrocarbonic 2-methyl-5-vinylpyridine chain fragments of the polyampholyte play an important role in the association of similarly charged particals. It was shown that besides this effect of chain fragments of 2-methyl-5-vinylpyridine a significant contribution in the association is made by non-polar interactions, created by methyl groups in copolymer 2-methyl-5-vinylpyridine and methacrylic acid. The association mechanism and structure of the formed complexes was studied. It was shown that complex formation is accompanied by non-equal distribution of the chain copolymer between the protein globules and appearance of asymmetric particles of the complex. A correlation between the ability of polyampholytes to bind protein and their physiological action was found.