title: Immobilization of S-methyltransferase.
abstract: S-methyltransferase was solubilized from pig liver microsomes by treatment with N-dodecyl-N,N-dimethyl-3-ammonio-1-sulfonate (Zwittergent). The soluble enzyme was immobilized by covalent binding to agarose and by copolymerization with acrylamide. The specific activity for the agarose-bound enzyme towards the substrate ethane thiol was 0.87 nmol/min/mg and for the acrylamide-bound enzyme 0.55 nmol/min/mg. The specific activity of the soluble enzyme was found to vary with increasing chain length of the substrate molecules from 0.5 nmol/min/mg for methane thiol (C1) to 6.3 nmol/min/mg for n-heptane thiol (C7). After binding of the enzyme to agarose beads, the increase in specific activity towards substrates with increasing chain length was no longer detectable. Instead, a relatively constant specific activity of 1.1 nmol/min/mg was observed for the whole range of substrates tested from C1 to C7. The stability of the agarose immobilized enzyme at -20 degrees C is twice as good as the soluble enzyme. The acrylamide immobilized enzyme is less stable than the soluble enzyme.
mesh_terms: D000818:Animals; D004355:Drug Stability; D004800:Enzymes, Immobilized / Q000378:metabolism*; D007700:Kinetics; D008780:Methyltransferases / Q000378:metabolism*; D008862:Microsomes, Liver / Q000201:enzymology*; D012685:Sepharose; D013552:Swine
chemical_list: D004800:Enzymes, Immobilized; D012685:Sepharose; D008780:Methyltransferases