Patent ID: 6664073
Filing Date: 2003-12-16
Classification: C12Q,Y10S

Abstract:
An enzymatic cycling assay for assessing the amount of homocysteine and/or cystathionine in a solution comprising:(a) contacting the solution containing homocysteine and/or cystathionine to form a reaction mixture, with cystathionine &bgr;-synthase, or a derivative thereof, L-serine, and cystathionine &bgr;-lyase, or a derivative thereof, for a time period sufficient to catalyze the cyclical conversion of homocysteine to cystathionine and the reconversion of cystathionine to homocysteine with the production of pyruvate and ammonia; (b) determining the amount of pyruvate and/or ammonia present in the reaction mixture; and (c) assessing the amount of homocysteine and/or cystathionine present in the solution based on the amount of pyruvate and/or ammonia produced, wherein the amount of pyruvate is determined by the enzymatic conversion of pyruvate to lactate and wherein the conversion of pyruvate to lactate is by the addition of lactate dehydrogenase, or a derivative thereof, and NADH, or a derivative thereof.