Stereochemical evidence for monomeric thiometaphosphate as an intermediate in the hydrolysis of (RP) and (SP)-deoxyadenosine 5′-[β-17O]-β-thiodiphosphate

Abstract

(R_P)-Deoxyadenosine 5′-[β-¹⁷O]-β-thiodiphosphate is hydrolysed in (¹⁸O)water at pH 7.2 (where it is present as its trianion) to AMP and inorganic [¹⁶O, ¹⁷O, ¹⁸O]thiophosphate with complete inversion of configuration at phosphorus, whereas at pH 4.5 (where it is present as its dianion) hydrolysis occurs with 50% racemisation and 50% inversion, indicating that ‘liberated’ metathiophosphate can exist and has a finite lifetime in aqueous solution under these conditions.