title: Isolation and identification of a small molecular weight inhibitor of cyclic nucleotide phosphodiesterase from bovine brain.
abstract: In a search for endogenous regulators for cyclic nucleotide phosphodiesterase (3':5'-cyclic-AMP 5'-nucleotidohydrolase, EC 3.1.4.17), we found that the ultrafiltrate of bovine brain homogenate contained a cyclic nucleotide phosphodiesterase inhibitor. The inhibitor-containing fraction was further purified by ion-exchange column chromatography and gel filtration chromatography. The purified inhibitor was found to be a small molecular weight compound which had a maximum absorption at 248 nm. This compound was identified by thin-layer chromatography and high-pressure liquid chromatography as hypoxanthine. We suggest that hypoxanthine may serve as an endogenous regulator for the hydrolysis of cyclic nucleotide by cyclic nucleotide phosphodiesterase.
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000037:antagonists & inhibitors*; D000818:Animals; D001921:Brain / Q000201:enzymology / Q000378:metabolism*; D002417:Cattle; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D007042:Hypoxanthines / Q000302:isolation & purification*; D007700:Kinetics
chemical_list: D007042:Hypoxanthines; D015105:3',5'-Cyclic-AMP Phosphodiesterases