Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or... – Involving oxidoreductase
Reexamination Certificate
2005-03-15
2005-03-15
Leary, Louise N. (Department: 1654)
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
Involving oxidoreductase
C435S015000, C435S018000, C435S004000, C435S968000
Reexamination Certificate
active
06867014
ABSTRACT:
The present invention provides an enzymatic cycling assay for assessing the amount of homocysteine and/or cystathionine in a solution such as blood, blood derivatives, or urine. The assay comprises the steps of contacting the solution containing homocysteine and/or cystathionine to form a reaction mixture, with CBS, or a derivative thereof, L-serine, and CBL, or a derivative thereof, for a time period sufficient to catalyze the cyclical conversion of homocysteine form to cystathionine and the reconversion of cystathionine to homocysteine with the production of pyruvate and ammonia; determining 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 of pyruvate and/or ammonia formed. Expression vectors and isolation procedures for CBS, or derivatives thereof, and CBL, or derivatives thereof, are also provided as well as test kits for carrying out the assay. In preferred embodiments, the assays can be conducted in 15 minutes or less, with a minimum of enzyme usage.
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Forest Doreen
Kawasaki Glenn
Lawson Sobomabo
Legaz Mark
Liedtke Raymond
Catch Inc.
Leary Louise N.
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