Enzymatic activities of coated vesicle fractions from bovine and rat cerebrums.
The changes in the enzymatic properties of coated vesicle fractions obtained from bovine cerebrums and rat forebrains were investigated as the preparation procedures were modified. Because Mg(2+)-dependent ATPase activity in the coated vesicle fractions that were prepared by conventional centrifugation methods appeared to derive from contaminating particulates, the activity was examined after further purification by column chromatography and confirmed by histochemical technique. Both the coat proteins and the vesicles enclosed in the coat networks failed to show the activity. Since plain synaptic vesicles are known to have ATPase activities, the results may indicate that the membrane structure of synaptic vesicles is modified between the coated vesicle stage and the plain vesicle stage of vesicle recycling as Heuser and Reese proposed (J. Cell Biol.57, 315-344, 1973). The comparison of the specific activity change in ATPase with those of acetylcholinesterase and NADPH-cytochrome c reductase suggested that there were two types of microsomes contaminating coated vesicle fractions that were prepared conventionally.
Goto
K
K
Department of Biochemistry, Nagoya City University Medical School, Mizuho-ku, Nagoya 467, Japan.
Tanaka
R
R