Trans-N-glycosidase studied with radioactive adenine

Abstract

The exchange between adenine and the hypoxanthine of hypoxanthine deoxyriboside catalysed by an enzyme prepn. from Lactobacillus helveticus was studied. Using C14- adenine the reaction gave rise to adenine deoxyriboside with a molar C14 concn. as high as that of the initial adenine. The reaction was therefore, not a transamination involving the 6-positions of adenine and hypoxanthine deoxyriboside, but was probably an exchange of the adenine skeleton with the bound hypoxanthine, catalysed by a trans-glycosidase. The enzyme prepn. catalysed an exchange reaction between the adenine of adenine deoxyriboside and C14-adenine. It also rapidly degraded adenine riboside (adenosine) by hydrolysis and deamination, but did not deaminate adenine deoxyriboside.