title: Regulation of cyclic GMP phosphodiesterase in the submandibular gland of adult rat.
abstract: Cyclic GMP phosphodiesterase was investigated in the submandibular gland of the adult rat to elucidate the regulatory mechanisms of cGMP concentration in this gland. Ca2+ sensitivity was easily demonstrated as in other tissues using EGTA in the buffer for elution from DEAE-cellulose. The presence of inhibitor proteins for basal and calmodulin-activated portions of Ca2+-dependent phosphodiesterase was suggested. The inhibitor for the basal activity of Ca2+-dependent phosphodiesterase was deemed to be a heat-labile protein, which decreased Vmax, but had no effect on the Km value for cGMP. The presence of more than one kind of inhibitor for the calmodulin-activated portion of the Ca2+-dependent phosphodiesterase was also suggested. One of these, which was not absorbed on DEAE-cellulose, was a heat-labile protein which caused an increase of Km for cGMP, but no change of Vmax.
mesh_terms: D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000032:analysis* / Q000037:antagonists & inhibitors; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002147:Calmodulin / Q000494:pharmacology; D002848:Chromatography, DEAE-Cellulose; D004789:Enzyme Activation; D007700:Kinetics; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013363:Submandibular Gland / Q000201:enzymology*
chemical_list: D002147:Calmodulin; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D002118:Calcium