In enzymatic creatinine determination, the initial reaction with creatininase produces which compound?

• A. Creatine
• B. Sarcosine
• C. Urea
• D. Ammonia

Answer: (A)

In enzymatic creatinine determination, the first step uses creatininase to act on creatinine and convert it to creatine. This hydrolysis cleaves the cyclic structure of creatinine, yielding creatine as the initial product. The next step then further processes creatine to sarcosine and urea. So creatine is the correct initial product because it is produced directly by the action of creatininase on creatinine. Sarcosine and urea arise in subsequent reactions.