Particulate guanylate cyclase of skeletal muscle. Effects of Ca2+ and other divalent cations on enzyme activity
| Autor: | H. Shelton Earp, Steven N. Levine, Alton L. Steiner, Gerhard Meissner |
|---|---|
| Rok vydání: | 1979 |
| Předmět: |
GUCY1B3
Ionophore Divalent medicine Animals Magnesium chemistry.chemical_classification Manganese Sarcolemma biology Muscles GUCY1A3 Guanylate cyclase activity Skeletal muscle General Medicine Enzyme assay Enzyme Activation Kinetics medicine.anatomical_structure Solubility Biochemistry chemistry Guanylate Cyclase biology.protein Calcium Guanosine Triphosphate Rabbits |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Enzymology. 566:171-182 |
| ISSN: | 0005-2744 |
| DOI: | 10.1016/0005-2744(79)90259-6 |
| Popis: | The properties of particulate guanylate cyclase (GTP pyrophosphate-lyase (cyclizing), EC 4.6.1.2) from purified rabbit skeletal muscle membrane fragments were studied. Four membrane fractions were prepared by sucrose gradient centrifugation and the fractions characterized by analysis of marker enzymes. Guanylate cyclase activity was highest in the fraction possessing enzymatic properties typical of sarcolemma, while fractions enriched with sarcoplasmic reticulum had lower activities. In the presence of suboptimal Mn2+ concentrations, Mg2+ stimulated particulate guanylate cyclase activity both before and after solubilization in 1% Triton X-100. Guanylate cyclase activity was biphasic in the presence of Ca2+. Increasing the Ca2+ concentration from 10(-8) to 10(-5) M decreased the specific activity. As the Ca2+ concentration was further increased to 5 . 10(-4) M enzyme activity again increased. After solubilization of the membranes in 1% Triton X-100, Ca2+ suppressed enzyme activity. Studies utilizing ionophore X537A indicated that the altered effect of Ca2+ upon the solubilized membranes was independent of asymmetric distribution of Ca2+ and Mg2+. |
| Databáze: | OpenAIRE |
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