Proteolytic Digestion of Cl^--ATPase in Rat Brain Synaptosomes

抄録

Upon tryptic digestion of synaptosomes, ATPase activities decreased in the order of Cl^--ATPase ?? Na⁺, K⁺-ATPase > anion-insensitive Mg²⁺-ATPase. Upon synaptosome treatment with hypotonic solution, C1^--ATPase or anion-insensitive Mg²⁺-ATPase was slightly inactivated, while Na⁺, K⁺-ATPase underwent a much larger degree of inactivation. ATP-Mg inhibited the ATPase digestion in the hypotonic-solution-treated synaptosomes in a concentration-dependent manner, but not in the untreated synaptosomes. These results suggest that trypsin-digestible site of C1^--ATPase are present on both sides of the synaptosomal plasma membrane, and the ATP-Mg binding site of the enzyme is located on the inner surface of the membrane.