ENZYMATIC-SYNTHESIS OF [METHYL-(H-2)3] CREATININE

2-Amino-1,5-dihydro-1-[methyl-H-2(3)] 4H-imidazol-4-one ([methyl-H-2(3)] creatinine) was obtained by acidification and heating (120-degrees-C, 120 min) of the [methyl -H-2(3)] N-amidinosarcosine (creatine) synthesised by methylation of guanidoacetate (GA) with S-adenosyl-[methyl-H-2(3)) L-methionine ([methyl-H-2(3)] AdoMet) in the presence of rat liver guanidoacetate methyltransferase (GAA-MT). Isotopic enrichment was 94.7 %.