Acyl-CoA synthetase catalyzes the synthesis of diadenosine hexaphosphate (Ap(6)A)

The synthesis of diadenosine hexaphosphate (Ap(6)A), a potent vasoconstrict or, is catalyzed by acyl-CoA synthetase from Pseudomonas fragi. In a first step AMP is transferred from ATP to tetrapolyphosphate (P-4) originating ad enosine pentaphosphate (p(5)A) which, subsequently, is the acceptor of anot her AMP moiety from ATP generating diadenosine hexaphosphate (Ap(6)A). Diad enosine pentaphosphate (Ap(5)A) and diadenosine tetraphosphate (Ap(4)A) wer e also synthesized in the course of the reaction. In view of the variety of biological effects described for these compounds the potential capacity of synthesis of diadenosine polyphosphates by the mammalian acyl-CoA syntheta ses may be relevant, (C) Societe francaise de biochimie et biologic molecul aire / Elsevier, Paris.