chondroitin-sulfates and quinone

The glycosaminoglycan microenvironment of testicular hyaluronidase was simulated by multipoint covalent attachment of the enzyme to glycans as a result of benzoquinone activation. The efficiency of their binding was assessed using gel chromatography, ultrafiltration, titration of surface amino groups of the enzyme, electrophoresis, as well as judging by the value of residual endoglycosidase activity and its inhibition with heparin. Copolymer glycosaminoglycans, such as dermatan sulfate and heparin, inactivated the endoglycosidase activity as a result the C-5 epimerization of hexuronic acid. It was shown that glucuronic acid and, to a lesser extent, N-acetylglucosamine determine the specificity of hyaluronidase. The chondroitin-sulfate microenvironment made the enzyme resistant to heparin inhibition because the equatorial orientation of the OH groups is similar to that in hyaluronic acid. Model experiments with dextran and dextran sulfate showed that sulfation of the glycan chain increased its rigidity, thus hampering the stabilizing effect on hyaluronidase. The effect of chondroitin sulfate on the endoglycosidase activity of hyaluronidase had additive character and did not directly affect the small fragment of the active site of the enzyme located at the bottom of a groove. The glycosaminoglycan microenvironment of hyaluronidase, containing an iduronic acid residue, the alpha1-3 and alpha1-4 glycosidic bond, inactivated the hyaluronidase activity of the enzyme, whereas simple polymers (such as gluco- and galactoaminoglycans) potentiated it due to a similar way of linking--beta(1e-4e) and beta(1e-3e). To understand the nature of these interactions in detail, the effect of oligomeric glycosaminoglycan fragments and their derivatives on hyaluronidase should be studied.

Topics: Animals; Benzoquinones; Cattle; Chondroitin Sulfates; Dermatan Sulfate; Enzyme Activation; Enzyme Inhibitors; Female; Glycosaminoglycans; Heparin; Humans; Hyaluronoglucosaminidase; Male; Skin; Swine; Testis; Trachea; Umbilical Cord

The interaction of superoxide dismutase with sodium chondroitin sulfate was studied. The enzyme easily forms both enzyme associations and non-covalent complexes with chondroitin sulfate in solution. The enzyme was chemically modified with benzoquinone-activated chondroitin sulfate. The electrophoresis and ultrafiltration data indicate the formation of covalently modified derivatives of superoxide dismutase. Almost half of the superoxide dismutase subunits were covalently bound to chondroitin sulfate; the modified subunit retained the ability to form dimers with the native subunit. The modified superoxide dismutase possesses high residual catalytic activity and is promising for biomedical investigations.

Topics: Benzoquinones; Catalysis; Chondroitin Sulfates; Dimerization; Electrophoresis, Polyacrylamide Gel; Protein Binding; Superoxide Dismutase; Ultrafiltration

Catalase was chemically modified by sodium chondroitin sulfate using the benzoquinone binding method. Thus, 40-42% of the catalase preparation was modified. Treatment of catalase and superoxide dismutase with benzoquinone-activated chondroitin sulfate results in a bienzymic conjugate with electrophoretically heterogenous composition. The yield of the products and their residual catalytic activity indicate that the method can be used for the preparation of modified catalase and the bienzymic conjugate to study their efficiency in vivo.

Topics: Benzoquinones; Catalase; Catalysis; Chondroitin Sulfates; Chromatography, Gel; Electrophoresis, Polyacrylamide Gel; Superoxide Dismutase