title: Purification and characterization of phosphodiesterase from the venom of Trimeresurus mucrosquamatus.
abstract: Phosphodiesterase was isolated from the venom of Trimeresurus mucrosquamatus from Taiwan using gel filtration on a Sephadex G-100 column, followed by anion or cation exchange chromatography. Phosphodiesterase was homogeneous as established by a single band on acrylamide gel electrophoresis and immunodiffusion. Phosphodiesterase activity was inhibited by ethylenediamine tetraacetic acid (EDTA), o-phenanthroline, thioglycolic acid or p-chloromercuribenzoate (PCMB) but not by soybean trypsin inhibitor (SBTI) or benzamidine. The molecular weight of this enzyme was determined to be approximately 140,000 and the isoelectric point was found to be pH 7.4 by isoelectric focusing with carrier ampholyte. The Michaelis constant (Km) of this enzyme for p-nitrophenyl thymidine-5'-phosphate and inhibition constant (Ki) for PCMB were found to be 5.6 X 10(-3) and 7.6 X 10(-4) M, respectively.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D003435:Crotalid Venoms / Q000302:isolation & purification*; D005779:Immunodiffusion; D007525:Isoelectric Focusing; D007700:Kinetics; D008970:Molecular Weight; D010727:Phosphoric Diester Hydrolases / Q000302:isolation & purification* / Q000378:metabolism; D012911:Snakes
chemical_list: D000596:Amino Acids; D003435:Crotalid Venoms; D010727:Phosphoric Diester Hydrolases