Calcium ion-regulated phospholipase C activity in bovine rod outer segments.
Bovine retinal rod outer segment membranes are enriched in a phosphoinositide-specific phosphodiesterase (phospholipase C) activity strictly modulated by free calcium ion concentration. The enzyme(s) was highly active on phosphatidylinositol 4,5-bisphosphate: maximal hydrolysis rate was attained at 10(-5)M Ca2+ and accounted for 91 +/- 4 nmoles hydrolyzed/min/mg of protein. The results support the notion that in vivo the enzyme(s) is regulated so as to conform to the phototransduction events.
Panfoli
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I
Istituto Policattedra di Chimica Biologica, Università degli Studi di Genova, Italy.
Morelli
A
A
Pepe
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I
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002417:Cattle; D003840:Deoxycholic Acid / Q000494:pharmacology; D007700:Kinetics; D019269:Phosphatidylinositol 4,5-Diphosphate; D010716:Phosphatidylinositols / Q000378:metabolism*; D012374:Rod Cell Outer Segment / Q000201:enzymology*; D010738:Type C Phospholipases / Q000378:metabolism*
D019269:Phosphatidylinositol 4,5-Diphosphate; D010716:Phosphatidylinositols; D003840:Deoxycholic Acid; D010738:Type C Phospholipases; D002118:Calcium