[Preparation of monoclonal antibodies to E1-component and their use for studying the pyruvate dehydrogenase complex].

A monoclonal antibody against the E1-component of pigeon breast muscle has been prepared. The dissociation constant of the E1-mAb F7F10 complex was determined to be equal to 5.93.10(-8) M. The cross-reaction between mAb F7F10 and the E1-component of the pyruvate dehydrogenase complex from various species (including human beings) was established. The F7F10 antibody was shown to interact with both alpha- and beta-subunits of E1, which suggests that the amino acid residues in the both subunits are constituents of the antigenic determinant. Binding of the F7F10 antibody to the antigen had no effect on the enzymatic activity of E1 but induced rapid inactivation of the pyruvate dehydrogenase complex in the pyruvate:NAD oxidoreductase reaction. The competition between the F7F10 antibody and the E2-component of the pyruvate dehydrogenase complex for the binding to E1 was revealed by immunoenzymatic analysis. It was concluded that the antigenic determinant and the E1 site responsible for the E1-E2 interaction within the pyruvate dehydrogenase complex may overlap.