THE CONCENTRATIONS OF SOME ENZYMES OF THE CITRIC ACID CYCLE AND ELECTRON TRANSPORT SYSTEM IN THE LARGE GRANULE FRACTION OF EGGS AND TROCHOPHORES OF THE OYSTER, CRASSOSTREA VIRGINICA

Abstract

Five enzymes of the citric acid cycle, as well as DPNH oxidase and DPNH-cytochrome c reductase, were measured in large visible granules (yolk, mitochondria, and other granules) and the supernatant (microsomal and soluble) fraction from homogenates of fertilized eggs and trochophores. The proportions of total [alpha]-ketoglutaric dehydrogenase, malic dehydrogenase, fumarase, and DPNH-cytochrome c reductase were found to increase in the granules during development. In the trochophore about one-third of the succinic dehydrogenase and DPNH oxidase was recovered in the supernatant fraction. Relative to succinic dehydrogenase, all of the enzymes except DPNH oxidase were higher in activity in the trochophore granules than in those of the egg. These changes appear to be a result of the differentiation of the population of large granules during development.