| 摘要 |
<p>The present invention provides an enzymatic cycling quantitative determination of homocysteine and / or cystathionine in solutions such as blood , blood and urine . Determination is the steps consisting in contacting a solution containing the same mocystein - and / or cystathionine in the reaction mixture with CBS, or a derivative thereof, L - serine and CBL, or a derivative thereof for a time sufficient to catalyze the conversion of the cyclic form of homocysteic cystathionine and reverse conversion of cystathionine to homocysteine the production of pyruvate and ammonia , in the determination of the amount of homocysteine and / or ammonia present in the reaction mixture and determining the amount of homocysteine and / or cystathionine present in the solution based on the amount incurred th pyruvate and / or ammonia . It also provides expression vectors and isolation procedures for CBS , or derivatives thereof , and CBL, or a derivative thereof as well as test kits for carrying out the assay. In a preferred embodiment, the determination may be carried out at an interval of 15 minutes or less with a minimum consumption of the enzyme .</p> |
