[Synthesis of cyclic AMP from renal cortex in vitro (author's transl)]

The parathyroid-hormone sensitive adenylate-cyclase from renal rat cortex has been studied. Mg2+ acts as stimulator at a specific locus increasing the apparent Vmax slightly from 50 to 60 nmol of cAMP per gram of protein if the Mg2+ concentration increases from 3.25 to 16 mM, and decreases the apparent KM from 2 to 0.4 mM. Fluoride decreases the apparent KM from 5 mM in NaF concentrations of 0 to 2 mM in NaF concentrations 2 mM. Magnesium ion also decreases the apparent Ka for NaF.