Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.6.1.1 (adenylate cyclase)
 19,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In previous studies we have proposed that the membrane-associated nucleoside diphosphate kinase (m-NDP kinase) may play a role as a GTP channeling machinery for adenylate cyclase regulation by hormones. In this study, whether the m-NDP kinase has a direct interaction with the component (GTP-binding protein (Gs)) of the glucagon- and beta-adrenergic agonist-sensitive adenylate cyclase systems in rat liver membranes was examined by extraction with octylglucoside, followed by immunoprecipitation by affinity-purified monospecific anti-NDP kinase antibodies. The results demonstrated that the m-NDP kinase and the Gs were extractable as a complexed form and that the complex formation was reversibly regulated, through cell surface receptors, by hormones which had an ability to cause activation of the rat liver adenylate cyclase. Also, it was suggested that guanine nucleotides rather than hormones were primary regulators of the m-NDP kinase-Gs interaction. These results were discussed in relation to the regulatory cycle of the Gs of adenylate cyclase system.
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PMID:Direct interaction between membrane-associated nucleoside diphosphate kinase and GTP-binding protein(Gs), and its regulation by hormones and guanine nucleotides. 283 81

Previous studies from this laboratory have proposed that membrane-associated nucleoside diphosphate kinase (m-NDP kinase) may play a role in regulation of adenylate cyclase by channeling GTP, an essential cofactor of adenylate cyclase regulation, into GTP-binding protein (Gs) in a hormone-dependent manner. To understand the true role of m-NDP kinase, in the present study, the m-NDP kinase was solubilized and purified to apparent homogeneity from rat liver purified plasma membranes and characterized in comparison with the cytosolic enzyme purified from the same tissue (s-NDP kinase). Some physical properties determined were: molecular weight (monomer), 18,300; sedimentation coefficient (s20,w), 6.2 S; isoelectric point (pI), 6.0. These values and kinetic parameters of the m-NDP kinase were almost identical to those of the s-NDP kinase whose characteristics were more extensively studied. A peptide mapping study of the 125I-labeled m- and s-NDP kinases gave essentially identical patterns. Polyclonal antibodies against the s-NDP kinase, which also cross-reacted with the m-NDP kinase, were prepared. Immunoblotting studies with the affinity-purified antibodies revealed that the monomer molecular weight of the purified m- and s-NDP kinases was identical to the values of unpurified enzymes present in membranes and crude extract. These results demonstrate that the purified m-NDP kinase underwent no remarkable modification during solubilization and purification, and that the m- and s-NDP kinases are quite similar in protein structure, if at all different. The physiological relevance of the m-NDP kinase in relation to the adenylate cyclase system is discussed.
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PMID:Membrane-associated nucleoside diphosphate kinase from rat liver. Purification, characterization, and comparison with cytosolic enzyme. 283 2