PARTIAL-PURIFICATION AND PROPERTIES OF THE CYTOPLASMIC FACTORS MODULATING ADENYLATE-CYCLASE ACTIVITY IN RAT LUNG PLASMA-MEMBRANES

The adult rat lung supernatant contains some factors which markedly enhance adenylate cyclase activity in membranes. These factors were separated into 2 less active components (peaks 1 and 2) by DEAE-cellulose chromatography. Their recombination restored the full activation of adenylate cyclase. Further purification and characterization of these factors revealed that the activator in peak 1 contained 2 proteins of low (14,500) and high (65,000) MW; the activator in peak 2 contained only 1 protein of 65,000. The kinetics of adenylate cyclase activation revealed that the Km and V [velocity] values were affected. Calmodulin was not involved in the cytoplasmic activation of adenylate cyclase in rat lungs.