COMPLEXES OF CHICKEN HEART LACTIC DEHYDROGENASE WITH COENZYMES AND SUBSTRATES

Incubation of chicken heart lactic dehydrogenase with DPN and pyruvate led to the formation of complexes in which the enzymatic activity was inhibited. These complexes were isolated over Sephadex and their spectral and chemical characteristics were investigated. Analogous complexes have been obtained with 3-acetyl pyridine DPN. A complex containing one molecule of coenzyme and one molecule of substrate per molecule of enzyme was isolated in the very early stages of incubation. Addition of sodium borohydride reduced the complexes. These reduced complexes were ibtained with DPN and with a number of DPN analogs. Also these complexes were isolated over Sephadex and they also showed inhibition of the enzymatic activity. The possible implications of these findings from the enzymological point of view are discussed. © 1968.