Clinica Chimica Acta 1989-12-15

Microbial enzymes for creatinine assay: a review.

S Shimizu, J M Kim, H Yamada

Index: Clin. Chim. Acta 185 , 241-52, (1989)

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Abstract

A novel metabolic pathway for the degradation of creatinine with N-methylhydantoin, N-carbamoylsarcosine and sarcosine as successive intermediates was found to operate in Pseudomonas putida 77 and many other microorganisms. Enzymes involved in this pathway were purified from cells of P. putida 77 and characterized. The first step, deimination of creatinine, is catalyzed by cytosine deaminase/creatinine deiminase. The following two steps, ring-opening of N-methylhydantoin and decarbamoylation of N-carbamoylsarcosine, are catalyzed by new enzymes, N-methylhydantoin amidohydrolase and N-carbamoylsarcosine amidohydrolase, respectively. The former requires ATP, Mg2+, and K+ for the hydrolysis and the reaction proceeds as follows: N-methylhydantoin + ATP + 2 H2O----N-carbamoylsarcosine + ADP + Pi. The latter catalyzes the following reaction; N-carbamoylsarcosine + H2O----sarcosine + NH3 + CO2. Sarcosine dehydrogenase was found to be the responsible enzyme for the oxidation of sarcosine to glycine in P. putida 77, but sarcosine oxidase was also found to be involved in this oxidation in several microorganisms. These enzymes were found to be useful tools for determination of creatinine.