Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Suramin has recently been used to treat patients with acquired immune deficiency syndrome because of the action of this drug on reverse transcriptase. Patients so treated developed the symptoms and hormonal profiles of adrenal insufficiency. To evaluate the mechanism of action of suramin on adrenalcortical function, adrenal mitochondrial and microsomal preparations from five subjects were assayed for steroidogenic enzyme activity in the presence and absence of suramin. Specifically, 3 beta-hydroxysteroid dehydrogenase/isomerase, 17 alpha-hydroxylase, 21-hydroxylase, 11 beta-hydroxylase, and 17,20-desmolase activities were measured in the presence of 0-5000 mumol/L suramin concentrations. In all assays, enzyme activities decreased in a dose-dependent fashion as suramin concentrations increased. The drug doses (calculated) that caused 50% inhibition of enzyme activity were: 21-hydroxylase activity, 50 mumol/L; 17 alpha-hydroxylase activity, 25 mumol/L; 17,20-desmolase activity, 50 mumol/L; 11 beta-hydroxylase, 2 mumol/L, and 3 beta-hydroxysteroid dehydrogenase/isomerase, 1200 mumol/L. These results suggest that suramin has a concentration-dependent inhibitory effect on the key P-450-regulated enzymatic steps in adrenal glucocorticoid steroidogenesis, which may explain the development of adrenal insufficiency in acquired immune deficiency syndrome patients treated with suramin.
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PMID:The inhibition of human adrenal steroidogenic enzyme activities by suramin. 246 3

Steroid 21-hydroxylase activity was assayed in low-speed supernatants prepared from whole cell homogenates of mouse and rat tissues. Kidney supernatants had an activity which was approximately 2-5% that of adrenal preparations while heart muscle was found to be without 21-hydroxylase activity. When the enzyme kinetics were characterized, both adrenal and kidney low-speed supernatants demonstrated saturation kinetics, but with very different Vmax and Km values. Using polymerase chain reaction amplification after reverse transcriptase synthesis of cDNA from isolated RNA (RT-PCR), we found low levels of mRNA for steroid 21-hydroxylase in mouse kidney, but none in heart muscle. Thus, extra-adrenal steroid 21-hydroxylase activity in the kidney may be mediated by the same enzyme as found in adrenals.
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PMID:Steroid 21-hydroxylase in the kidney: demonstration of levels of messenger RNA which correlate with the level of activity. 787 52