Effects of Antisera on Tyrosinase in Glomerella Extracts

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Abstract
Summary: Antisera produced in rabbits by the injection of Glomerella extracts rapidly inhibit, and slowly precipitate, the tyrosinase activity of the extracts. Effects of variations in substrate, antiserum, and extract concentrations suggest that a competitive relationship, perhaps of the sort that has been designated “kinetic competition,” prevails between at least a fraction of the antibodies and the substrate, with regard to the portion of the enzyme surface that includes its substrate-combining sites. Complexity of serum effects on the enzymatic activity, including dialyzable and nondialyzable inhibition and protection, activation, or reactivation of the enzyme, as well as characteristics of the course of the tyrosinase reaction itself, prevents the application of a rigorous kinetic analysis to this system at this time. Inhibition and precipitation of the enzymatic activity by antisera provide a delicate system to test for serological differences among Glomerella tyrosinases. Some of the factors involved in enzyme serology, important in this connection, are discussed.