The mechanism of displacement of sulphur from adenosine 5′-[(S)α-thio-γ-benzyl] triphosphate

Adenosine 5′-[(S)α-thio-γ-benzyl]triphosphate on treatment with cyanogen bromide in [18O]water gives [α-18O]- and [γ-18O]-adenosine 5′-[γ-benzyl]triphosphate in about equal amounts, the [α-18O] material being formed with retention of configuration at phosphorus providing support for a mechanism involving participation by the γ-phosphate group.