Enzymatic Determination of Homocysteine in Cell Extracts

摘要: Determination of homocysteine levels in cells and serum is important because high a risk factor for cardiovascular disease. The currently used methods analysis either are time consuming or rely on the use expensive equipment. Described this study an enzymatic assay that determines multiple samples less than 30 min at from 5 to 50 pmol using only spectrophotometer. reproducibility consistent with other used. A second assay, about 5-fold more sensitive, follows catalyzed solvent exchange protons glycine, which requires scintillation counter. Both spectrophotometric radiometric based conversion 5-methyltetrahydrofolate tetrahydrofolate by methionine synthase. formed stoichiometric amounts sample. In method catalytic three enzymes form metabolic cycle generates NADPH NADP+. required pro 2S proton glycine solvent. l-Cysteine, 30-fold higher upper level these assays, does not give any measurable response.