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Z Kiss

Publications and source records attributed to Z Kiss.

At least 145 records · Page 8Linked to original sources
PubMed1984

Guanine-nucleotide-dependent inhibition of adenylate cyclase of rabbit heart by glucagon.

The present study demonstrates an inhibitory effect of glucagon on the adenylate cyclase system of rabbit heart. Inhibition was maximal (22-40%) at 0.1-0.01 microM glucagon and required the presence of 0.01-0.1 mM GTP or guanosine 5'-[beta, gamma-imido]triphosphate (GuoPP[NH]P). Reduced or no inhibitor effect of glucagon was observed: (a) after limited proteolysis of plasma membrane proteins by trypsin, (b) in the presence of 1 mM Mn2+, (c) in the absence of Na+, and (d) during the first 10 min of incubation if GuoPP[NH]P was the activating ligand. With GTP as the activating ligand, inhibition of cyclase by glucagon occurred without delay. These data are consistent with a mediation of glucagon inhibition by a guanine-nucleotide-binding protein. In the presence of ethanol (0.2 M) or benzyl alcohol (0.05 M), agents which are known to increase the fluidity of biological membranes, glucagon increased the enzyme activity in a guanine-nucleotide-dependent manner. Activation of cyclase in the presence of alcohols was maximal (30-60%) at 0.1-1.0 microM glucagon and 0.01 mM guanine nucleotides. Data suggest that glucagon receptors can interact with both the activatory and inhibitory guanine-nucleotide-binding proteins and the physical state of membranes may play a role in determining which interaction will be preferential.

Adenylyl Cyclase Inhibitors↗
PubMed1982

Rat liver plasma membranes contain a lipid-dependent protein kinase activity.

The treatment of rat liver plasma membranes with EDTA resulted in substantial release of a protein kinase activity. Using histones as external substrates both phosphatidylserine (PS) and diolein activated the enzyme. The activatory effect of PS but not that of diolein depended on Ca2+. In contrast, the enzyme activity was inhibited by both PS and diolein when the substrate was protamine. The inhibition by PS, unlike by diolein, depended on Ca2+. Data suggest that mobilization of plasma membrane-bound Ca2+ by physiological stimuli may be accompanied by release of the lipid-dependent protein kinase into the cytoplasm.

Animals↗