Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.6.1.2 (guanylate cyclase)
 8,497 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A procedure has been developed for the isolation of cone photoreceptors from the retina of the lizard Anolis carolinensis in order to study the effects of dark- and light-adaptation on the cyclic nucleotide metabolism of these visual cells. Incubation of the retina in N2 medium with hyaluronidase and DNAase allows us to obtain intact photoreceptors with good purity (85-90%), yields (greater than 2 x 10(5) cells per retina), and more than 95% of them excluding Trypan blue. cAMP levels are 20-fold higher than cGMP levels in cells from dark-adapted animals and are decreased by 35% upon exposure to light, whereas cGMP levels show no apparent change. However, both cAMP- and cGMP-phosphodiesterases, as well as adenylate and guanylate cyclase, are activated several-fold by light, but the enzymes involved in cGMP metabolism have higher Vmaxs than the cAMP related enzymes. The apparent constant levels of cGMP found in cone photoreceptors may result from our inability to detect the very fast changes that occur in these cells when they are exposed to light.
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PMID:The effects of light on cyclic nucleotide metabolism of isolated cone photoreceptors. 134 77

We have previously reported that a crude aqueous extract of the bitter melon (Momordica charantia) has both cytostatic and cytotoxic activities, and is a competitive inhibitor of guanylate cyclase activity. This crude preparation kills human leukemic lymphocytes in a dose-dependent manner while not affecting the viability of normal human lymphocytes at these same doses. In this report we describe the purification and characterization of one of these cytostatic factors which also exhibits anti-viral activity. The partially purified factor was both cytostatic to BHK-21 cells and inhibitory to VSV plaque formation in a dose-dependent manner. This preparation was inhibitory to both viral and host cell RNA and protein synthesis as early as 30 min after addition to these samples. As determined by gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), this purified factor is a single component with a molecular weight corresponding to 40,000 daltons. The factor is sensitive to boiling and to pre-treatments with trypsin, but not ribonuclease (RNAse), or deoxyribonuclease (DNAse). As determined by radioactive precursor uptake and incorporation studies, the purified factor inhibits both RNA and protein synthesis in intact tissue culture cells and inhibits protein synthesis in a cell-free wheat germ system. DNA synthesis was slightly stimulated. The purified factor is cytostatic for both BHK-21 and for the IM9 leukemic cell lines for at least 120 h. The cytostatic component had no effect on cellular cyclic GMP metabolism.
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PMID:Purification and characterization of a cytostatic factor with anti-viral activity from the bitter melon. 614 53

We have previously reported that a crude aqueous extract of the bitter melon (Momordica charantia) has both cytostatic and cytotoxic activities, and is a competitive inhibitor of guanylate cyclase activity. This crude preparation kills human leukemic lymphocytes in a dose-dependent manner while not affecting the viability of normal human lymphocytes at these same doses. In this report we describe the purification and characterization of one of these cytostatic factors which also exhibits anti-viral activity. The partially purified factor was both cytostatic to BHK-21 cells and inhibitory to VSV plaque formation in a dose-dependent manner. This preparation was inhibitory to both viral and host cell RNA and protein synthesis as early as 30 min after addition to these samples. As determined by gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), this purified factor is a single component with a molecular weight corresponding to 40,000 daltons. The factor is sensitive to boiling and to pre-treatments with trypsin, but not ribonuclease (RNAse), or deoxyribonuclease (DNAse). As determined by radioactive precursor uptake and incorporation studies, the purified factor inhibits both RNA and protein synthesis in intact tissue culture cells and inhibits protein synthesis in a cell-free wheat germ system. DNA synthesis was slightly stimulated. The purified factor is cytostatic for both BHK-21 and for the IM9 leukemic cell lines for at least 120 h. The cytostatic component had no effect on cellular cyclic GMP metabolism.
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PMID:Purification and characterization of a cytostatic factor with anti-viral activity from the bitter melon. 619 72