Effect of phospholipase A2 on Ca2+-stimulated adenosine triphosphatase activity in microsomal fraction of rat submandibular gland.
The effect of phospholipase A2 on the Ca2+-ATPase (EC 3.6.1.3) activity in the microsomal fraction of rat submandibular gland was kinetically studied in vitro. The Ca2+-ATPase activity was significantly increased by the treatment with phospholipase A2 in the presence of bovine serum albumin as a scavenger for hydrolyzed products. When the microsomal fraction was incubated with phospholipase A2 in the absence of bovine serum albumin, the Ca2+-ATPase activity was not altered. The Vmax and Km values for both ATP and Ca2+ were increased by the phospholipase A2 treatment, respectively. These results indicated that the activation of Ca2+-ATPase by the phospholipase A2 treatment is due to the increase of Vmax.
Takamura
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K
Hayakawa
M
M
D000818:Animals; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002417:Cattle; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008297:Male; D008861:Microsomes / Q000201:enzymology*; D010179:Pancreas / Q000201:enzymology; D010740:Phospholipases / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism* / Q000494:pharmacology; D054467:Phospholipases A2; D051381:Rats; D011919:Rats, Inbred Strains; D012710:Serum Albumin, Bovine / Q000494:pharmacology; D013363:Submandibular Gland / Q000201:enzymology*
D012710:Serum Albumin, Bovine; D010740:Phospholipases; D010741:Phospholipases A; D054467:Phospholipases A2; D000252:Calcium-Transporting ATPases