THE SUBCELLULAR DISTRIBUTIONS OF SOME HYDROLYTIC ENZYMES IN UNFERTILIZED EGGS OF THE SEA URCHIN, ARBACIA PUNCTULATA

¹ Department of Biology, College of William Mary, Williamsburg, Virginia 23185

Differential centrifugation and density gradient centrifugation have been applied to nuclei-free homogenates of unfertilized eggs and adult gut of Arbacia, to determine the distributions of several hydrolytic enzymes and of nucleic acid and protein. Two types of large visible granules have been partially separated from egg homogenates by gradient centrifugation. The first type is rich in acid phosphatase and esterase; the second contains sulfatase, RNAase and nucleic acid. The activities of the above enzymes have also been determined im microsomal and soluble fractions of the egg, and the distribution of acid phosphatase and esterase have also been determined in the major subcellular fractions of the adult gut of Arbacia. In both types of homogenates hydrolytic enzymes were found to be present in submicroscopic granules and in the supernatant fluid. The major difference in the two types of material is that large granules containing the enzymes are present in the eggs but not in the gut tissue.