A Ca2+-sensitive cyclic-3',5'-nucleotide phosphodiesterase from sheep lung modulated by a tightly bound endogenous calmodulin.
Highly purified sheep lung cyclic-3',5'-nucleotide phosphodiesterase was sensitive to Ca2+/EGTA but insensitive to exogenous calmodulin. The Ca2+-sensitivity was inhibited by trifluoperazine. Heat-treated enzyme could activate a calmodulin-deficient phosphodiesterase, suggesting the presence of endogenous calmodulin in sheep lung cyclic-3',5'-nucleotide phosphodiesterase, possibly associated with the enzyme in a Ca2+-independent manner.
Radhakrishnan
T S
TS
Department of Biochemistry, Vallabhbhai Patel Chest Institute, University of Delhi, India.
Savithri
H S
HS
Rao
N A
NA
Venkitasubramanian
T A
TA
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology*; D004533:Egtazic Acid / Q000494:pharmacology; D005615:Freezing; D006358:Hot Temperature; D006868:Hydrolysis; D008168:Lung / Q000201:enzymology*; D012756:Sheep; D014268:Trifluoperazine / Q000494:pharmacology
D002147:Calmodulin; D014268:Trifluoperazine; D004533:Egtazic Acid; D002118:Calcium