The application of the diacetyl reaction to the estimation of creatine in urine

Abstract

Factors in urine affecting the diacetyl reaction for creatine were studied. These were found to be the large amts. of creatinine present, which yield significant amts. of creatine by hydrolysis during the test and the presence of NH-compound inhibitors which are not removed by p-chloromercuribenzoic acid. A method is descr. for the direct detn. of creatine in urine. An aliquot of urine was incubated with a suspension of a pseudomonad, containing a specific creatinase. After centri-fuging, p-chloromercuribenzoic acid was added to this and to untreated urine, and the rate of color development with [image]-naphthol and diacetyl detd. for these samples alone and with added creatine and added creatinine. The creatine content of the urine is detd. by extrapolation.