Purification and properties of a glycerophosphocholine phosphodiesterase from bovine brain myelin.
An enzyme releasing phosphocholine from glycerophosphocholine was purified to apparent homogeneity based upon SDS-PAGE. The enzyme was liberated from lyophilized bovine myelin by differential detergent extraction and final purification was accomplished with Q-Sepharose Fast Flow chromatography yielding an apparently homogeneous protein. The molecular mass based upon PAGE was approximately 14 kDa. The enzyme was also capable of releasing p-nitrophenol from p-nitrophenyl-phosphocholine. Maximal activity was obtained with 0.2 mM ZnCl2 or 1 mM CoCl2. p-Nitrophenylphosphocholine and phosphocholine were competitive inhibitors of glycerophosphocholine hydrolysis with Ki's of 0.028 mM and 0.03 mM respectively. Glycerophosphocholine and phosphocholine were competitive inhibitors of p-nitrophenylphosphocholine hydrolysis with Ki's of 0.5 mM and 1.75 mM respectively.
Yuan
J
J
Department of Biochemistry and Molecular Biology, University of Manitoba, Winnipeg, Canada.
Kanfer
J N
JN
D000818:Animals; D001921:Brain / Q000201:enzymology*; D002412:Cations / Q000494:pharmacology; D002417:Cattle; D002852:Chromatography, Ion Exchange; D002853:Chromatography, Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D008970:Molecular Weight; D009186:Myelin Sheath / Q000201:enzymology*; D010727:Phosphoric Diester Hydrolases / Q000302:isolation & purification* / Q000378:metabolism*; D013379:Substrate Specificity
D002412:Cations; D010727:Phosphoric Diester Hydrolases; C020677:glycerophosphocholine phosphodiesterase