Proteolytic digestion of Cl(-)-ATPase in rat brain synaptosomes.
Upon tryptic digestion of synaptosomes, ATPase activities decreased in the order of Cl(-)-ATPase greater than or equal to Na+,K+-ATPase greater than anion-insensitive Mg2+-ATPase. Upon synaptosome treatment with hypotonic solution, Cl(-)-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 Cl(-)-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.
Kunugi-Uehara
Y
Y
Department of Biology, Kyoto Pharmaceutical University, Japan.
Hashimoto
Y
Y
Ogura
C
C
Inagaki
C
C
Nishino
T
T
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D027321:Anion Transport Proteins; D001921:Brain / Q000201:enzymology* / Q000648:ultrastructure; D051381:Rats; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013574:Synaptosomes / Q000201:enzymology*; D014357:Trypsin
D027321:Anion Transport Proteins; D014357:Trypsin; D000251:Adenosine Triphosphatases; C031652:anion-sensitive ATPases; D000254:Sodium-Potassium-Exchanging ATPase