Chromate, molybdate, tungstate and vanadate behave as substrates of yeast diadenosine 5',5'''-p1,p4-tetraphosphate alpha, beta-phosphorylase.

Diadenosine 5',5'''-p1,p4-tetraphosphate (Ap4A) alpha, beta-phosphorylase from yeast Saccharomyces cerevisiae catalyzes two reactions: Ap4A cleavage and nucleoside diphosphate--phosphate (NDP-Pi) exchange. In both reactions phosphate can be substituted by arsenate, chromate, molybdate, tungstate or vanadate. In the presence of each anion, nucleoside 5'-monophosphate (NMP) always accumulates as a product of the reaction. This indicates that an unstable NMP anion is formed as an intermediate.