| 摘要 |
<p>Disclosed are novel methyltransferase assay methods, comprising: including, in a reaction mixture for a methyltransferase activity, a purified or recombinant adenosine nucleosidase activity that catalyses release of an adenine or adenine derivative moiety from a transmethylation product, and a purified or recombinant adenine deaminase activity that catalyses deamination of the released moiety to hypoxanthine or respective derivative and ammonia, wherein the methyltransferase activity is rate-limiting; and determining the methyltransferase activity by spectrophotometric or chromatographic monitoring of the coupled deamination reaction products, or of subsequent enzymatic or chemical reactions coupled thereto. Coupled oxidation of the hypoxanthine to uric acid and hydrogen peroxide is optionally affected using purified or recombinant xanthine oxidase, wherein the methyltransferase activity is rate-limiting, and wherein determining the methyltransferase activity comprises monitoring of the coupled oxidation reaction. Variations are disclosed comprises monitoring of reaction products (e.g., to detect NH3, Hypoxanthine, H2O2, and Uric Acid).</p> |
