Protein-O-carboxylmethyltransferase from cytosol and membranes of chicken erythrocytes.
Cytosolic protein-O-carboxylmethyltransferase was purified more than 4,000-fold in specific activity and membrane-associated protein-O-carboxylmethyltransferase carboxymethylase about 900-fold from chicken erythrocytes by use of a combination of affinity chromatography on immobilized S-adenosyl-L-homocysteine and gel filtration on Sephacryl S-200 (Pharmacia), together with 3-((3-cholamidopropyl)-dimethylammonio)-1-propane-sulfonate as a detergent to solubilize the membrane-associated enzyme. The two enzymes were characterized by examining the dependence of their activity on pH and on concentration of S-adenosyl-L-methionine using fetuin as an exogenous methyl-acceptor substrate, and were found to differ somewhat. The cytosolic enzyme had a pH optimum of 6.0 with an apparent Km value of 2.1 microM for S-adenosyl-L-methionine, whereas corresponding values for the membrane-associated enzyme were 6.5 and 0.71 microM. This report deals with the biochemical differences between purified cytosolic and membrane-associated protein carboxymethylase from the same cell source.
Saido
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TC
Division of Chemical Toxicology and Immunochemistry, Faculty of Pharmaceutical Sciences, University of Tokyo.
Toyoshima
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S
Osawa
T
T
D000818:Animals; D002645:Chickens; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D003600:Cytosol / Q000201:enzymology; D004910:Erythrocyte Membrane / Q000201:enzymology*; D004912:Erythrocytes / Q000201:enzymology*; D007700:Kinetics; D008970:Molecular Weight; D011496:Protein Methyltransferases / Q000097:blood*; D011497:Protein O-Methyltransferase / Q000097:blood* / Q000302:isolation & purification
D011496:Protein Methyltransferases; D011497:Protein O-Methyltransferase