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Properties of Detergent‐Dispersed Adenylate Cyclase from Cerebral Cortex. Presence of an Inhibitor Protein
Author(s) -
Sano Mamoru,
Drummond George I.
Publication year - 1982
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1982.tb12523.x
Subject(s) - cyclase , adenylate kinase , calmodulin , chemistry , biochemistry , phosphodiesterase , atpase , cerebral cortex , size exclusion chromatography , enzyme , chromatography , biology , endocrinology
Adenylate cyclase was solubilized from washed paniculate fraction of rabbit cerebral cortex with the nonionic detergent Lubrol 12A9 and subjected to either gel filtration on Ultrogel AcA 34 or chromatography on DEAE Bio‐Gel A. By both procedures the enzyme was resolved into two components, one insensitive to guanyl 5′‐yl imidodiphosphate [Gpp(NH)p] and NaF but stimulated by Ca 2+ and calmodulin, and another that was sensitive to Gpp(NH)p and NaF but relatively insensitive to Ca 2+ and calmodulin. The data support the possibility that two independent forms of adenylate cyclase exist in cerebral cortex, one regulated by guanine nucleotide regulatory protein and another by Ca 2+ ‐calmodulin. Fractions containing the guanylnucleotide‐sensitive activity were found to contain a factor that inhibited basal and Ca 2+ ‐stimulated adenylate cyclase in the Ca 2+ ‐sensitive fraction. The inhibitor was inactivated by heating at 60°C and by incubation with trypsin. Inhibition was not time‐dependent, and it was not due to destruction of cAMP by phosphodiesterase or of ATP by ATPase. Inhibitory action was not reversed by calmodulin and therefore it does not appear to be a calmodulin binding protein. Sucrose density gradient sedimentation indicated a sedimentation coefficient of 4S for the inhibitor; by this technique it co‐sedimented with the adenylate cyclase sensitive to Gpp(NH)p and NaF.