Activation of solubilized liver membrane adenylate cyclase by nucleotides
Review articleOpen access
1973/08/21 Full-length article DOI: 10.1016/0006-291X(73)90579-2
Journal: Biochemical and Biophysical Research Communications
AbstractLiver plasma membranes isolated from hypophysectomized rats were treated with 0.1 M Lubrol-PX, a nonionic detergent, and centrifuged at 165,000 × g for 1 hour. Adenylate cyclase activity remaining in the supernate had a specific activity that was at least equal to that of the particulate enzyme. The activity of the solubilized, non-sedimentable adenylate cyclase, as well as the membrane bound enzyme, was increased by GTP, ITP, and GMP-PCP at 10−4 M. The activity of the solubilized, non-sedimentable enzyme increased linearly with GTP from 10−6 to 10−4 M but there was no further increase in the activity of the solubilized enzyme with 10−3 M GTP. In contrast, the particulate liver membrane enzyme activity increased exponentially with GTP from 10−6 to 10−4 M and was further increased by 10−3 M GTP. These data indicate that GTP, ITP or GMP-PCP have direct effects on solubilized adenylate cyclase. This effect is in addition to a role of nucleotides in modifying membrane structure (16).
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