Malic Dehyrogenases in Sea Urchin Eggs.

Unfertilized Arbacia eggs have five electrophoretically distinct malic dehydrogenases which differ in their rates with pyridine nucleotide analogs. Both the number of peaks and their relative size change during early embryonic development. A D-malic dehydrogenase which utilizes the 3-acetylpyridine analog of DPN but not DPN itself was found. Electrophoresis on starch gel results in five peaks, all of which differ from the peaks of the L-malic dehydrogenases.