Malic Dehydrogenase Isozymes: Distribution in Developing Nucleate and Anucleate Halves of Sea Urchin Eggs

Abstract

Nucleate and anucleate halves of sea urchin eggs have seven and five forms of L-malic dehydrogenase, respectively. Fertilization results in reduction of the number of enzyme forms in both halves. The normal complement of seven isozymes in unfertilized eggs appears to be a synthesis of five soluble and four particulate forms. Reduction in the number of isozymes after fertilization takes place principally in solutble forms and appears to be under cytoplasmic control.