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.