The specificity of yeast low-Km cyclic AMP phosphodiesterase towards free bivalent metal ions and the diastereoisomers of cyclic adenosine phosphorothioate

摘要

pThe relative activity of a zinc-containing cyclic AMP phosphodiesterase towards the (Sp)- compared with the (Rp)-diastereoisomer of cyclic adensine phosphorothioate varied with the identity of the free bivalent metal ion from more than 35 to 0.074 along the series Mg2+ greater than Mn2+ greater than Co2+ greater than Zn2+ greater than Cd2+, showing that this ion, and not the tightly bound zinc, bonds to the phosphorothioate moiety of the substrate./p