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)

Healthy subjects were administered single oral doses of 800 mg or 400 mg 3-[2-(benzoxazol-2-yl)ethyl]-5-ethyl-6-methylpyridin-2(1H)-o ne (L-696,229), a nonnucleoside inhibitor of the human immunodeficiency virus-type 1 (HIV-1) reverse transcriptase (RT). Plasma or urine samples were collected over a period of 48 hr. Pooled plasma (0.5-6 hr) and urine (0-24 hr) samples were analyzed by HPLC-UV and HIV-1 RT inhibition assay using poly rC.dG as a template primer. The parent compound and several common metabolites were detected in both samples. The metabolic profiles were also similar to those obtained from a rat liver slice incubation with [3H]L-696,229. The in vitro metabolites were identified by NMR and MS as 5 alpha-hydroxyethyl- (major), 5,6-dihydrodiol-, 6'-hydroxy-, 6-hydroxymethyl-, and 5-vinyl analogs, and a benzoxazole ring hydrolysis product. Most of the significant metabolites in human plasma and urine were found to be identical to the in vitro metabolites, as established by HPLC-UV and MS. Hydrolysis of the plasma and urine with beta-glucuronidase/sulfatase indicated the presence of significant amounts of conjugates of the parent compound and 5 alpha-hydroxyethyl metabolite. Most of the other primary metabolites were also present in conjugated forms, albeit in small quantities. In addition, two secondary metabolites were isolated and identified from the hydrolyzed urine as 5-acetyl-6'-hydroxy- and 5 alpha-hydroxyethyl-6-hydroxymethyl- analogs.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Metabolism of 3-[2-(benzoxazol-2-yl)ethyl]-5-ethyl-6-methylpyridin-2 (1H)-one (L-696,229), an HIV-1 reverse transcriptase inhibitor, by rat liver slices and in humans. 751 52

Steroid sulfatase (STS) is a single enzyme with a range of substrate specificities, including estrone sulfate. Using a 2.4 kb cDNA clone, expression of human STS was undetectable by Northern hybridization, but STS RNA was detected in human placenta, human breast cancer samples, and in breast carcinoma cell lines following reverse transcriptase-PCR amplification, using specific primers to yield a product of 472 bp. In preliminary studies, stimulation of MCF-7 cell lines with estradiol (10(-8) M) resulted in an increased level of amplifiable STS RNA, and this upregulation of STS RNA could be abolished by tamoxifen. The estrone sulfatase activity in mammary tumors derived from N-nitrosomethylurea (NMU) treated rats was significantly decreased in animals treated with tamoxifen compared to control animals, regardless of the response of the tumors to the antiestrogen (P < 0.05). Although tamoxifen does not inhibit the estrone sulfatase enzyme in vitro, it may modulate the expression of STS RNA and the enzyme activity in vivo.
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PMID:Detection of breast cancer-associated estrone sulfatase in breast cancer biopsies and cell lines using polymerase chain reaction. 866 67

Expression analysis by reverse transcriptase (RT)-PCR indicates that human adipose tissue is not likely to perform de novo synthesis of steroid hormones from cholesterol because the mRNAs of cytochromes P450scc and P450c17, and of the steroidogenic-related proteins, steroidogenic acute regulatory protein and steroidogenic factor 1, were not detected. Instead, our data support an intracrine role of adipose tissue, in which adrenal dehydroepiandrosterone sulfate (DHEA-S), the most abundant circulating androgen in man, is selectively uptaken, desulfated, and converted into bioactive androgens and estrogens. Three organic anion-transporting polypeptides-B, -D, and -E, presumably involved in DHEA-S transmembrane transport, were demonstrated at the mRNA level. While sulfotransferase expression was not found, the occurrence of steroid sulfatase (STS), converting DHEA-S to DHEA, was established at the mRNA, protein and catalytic activity levels. The 5'-rapid amplification of cDNA ends analysis showed that STS transcription in adipose tissue is regulated by the use of two promoters which differ from the prevalent placental one. The adipose transcripts contain a distinct untranslated first exon, 0a or 0b, followed by a common partially translated exon 1b, and nine other exons that are also shared by the main placental transcript. The presence of an upstream open reading frame in the new transcript variants could lead to an N-terminal divergence restricted to the cleavable signal peptide and thus not interfering with the catalytic activity of the mature STS protein. The adipose transcripts are also present in the placenta as minor isoforms. Western blotting revealed the characteristic approximately 64 kDa band of STS in both the placenta and adipose tissue. The specific enzymatic activity of STS in adipocytes was 118 pmol/10(6) cells per hour, about 50-100 times lower than in the placenta. A similar rate of [3H] DHEA-S uptake plus desulfation was measured in preadipocytes and adipocytes, equivalent to 40-45 pmol/10(6) cells per hour. Thus, an excessive accumulation of fat may out-compete other peripheral organs that are also dependent on intracrine DHEA-S utilization, especially when the adrenal production is low or declining with aging.
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PMID:Tissue-specific transcriptional initiation and activity of steroid sulfatase complementing dehydroepiandrosterone sulfate uptake and intracrine steroid activations in human adipose tissue. 1683 17

MPS VI is an autosomal recessive disorder which occurs due to the deficiency of N-acetyl galactosamine-4-sulfatase (Arylsulfatase B - ARSB) involved in catabolism of dermatan sulfate resulting from disease-causing variations in the ARSB gene. Human Gene Mutation Database (HGMD) search revealed 200 different mutations in ARSB worldwide. In the present study we carried out molecular and functional analyses to characterize the mutations reported by us in Indian population. Mutation analysis of 19 MPS VI patients revealed presence of a total of 15 different mutations of which twelve were novel [p.Asp53Asn (c.157G>A; p.D53N), p.Leu98Arg (c.293T>G; p.L98R), p.Tyr103Serfs*9 (c.306_312delCTACCAG+146del; p.Y103Sfs*9), p.Phe166Leufs*18 (c.496delT; p.F166Lfs*18), p.Ile220Serfs*5 (c.659_660delTA; p.I220Sfs*5), p.Ile350Phe (c.1048A>T; p.I350F), p.Trp353* (c.1059G>A; p.W353*), p.His393Arg (c.1178A>G; p.H393R), p.Ser403Tyrfs* (c.1208delC; p.S403Yfs*), p.Pro445Leu (c.1334C>T; p.P445L), p.Trp450Leu (c.1349G>T; p.W450L) and p.Trp450Cys (c.1350G>C; p.W450C)] and three were known mutations [p.Asp54Asn (c.160G>A; p.D54N), p.Ala237Asp (c.710C>A; p.A237D) and p.Ser320Arg (c.960C>G; p.S320R)]. Functional characterization using site-directed mutagenesis followed by cell transfection assays, immunoblot, reverse transcriptase PCR and immunofluorescence studies for the putative pathogenic variants detected in our MPS VI patient cohort helped us to confirm the pathogenic potential of the variants in ARSB.
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PMID:Functional characterization of arylsulfatase B mutations in Indian patients with Maroteaux-Lamy syndrome (mucopolysaccharidosis type VI). 2782 22