The chemotactic effect of 5′-amido analogues of adenosine cyclic 3′,5′-monophosphate in the cellular slime moulds

Previously it was shown that amoebae of some Dictyostelium species are attracted by adenosine cyclic 3′,5′-monophosphate (cyclic AMP), and to a lesser extent, by the analogues of this nucleotide.We measured the chemotactic activity of several 5′-amido analogues of cyclic AMP by using a small population assay.Our investigations have shown unequivocally that the molecular receptor systems of cyclic AMP of the amoebae are highly sensitive to stereochemical alternation at the 5′position of the cyclophosphate ring, while the replacement of oxygen by nitrogen seems to exert no major influence. Alteration of the stereochemical envelope of the ring by a protruding group decisively alters the biological activity of the molecule, an effect which clearly does not depend on the type ot the group which protrudes.