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  1 / 29 MEDLINE  
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[PMID]:22001566
[Au] Autor:Yoshimoto FK; Desilets MC; Auchus RJ
[Ad] Endereço:Division of Endocrinology & Metabolism, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX 75390-8857, United States.
[Ti] Título:Synthesis of halogenated pregnanes, mechanistic probes of steroid hydroxylases CYP17A1 and CYP21A2.
[So] Source:J Steroid Biochem Mol Biol;128(1-2):38-50, 2012 Jan.
[Is] ISSN:1879-1220
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The human steroidogenic cytochromes P450 CYP17A1 (P450c17, 17α-hydroxylase/17,20-lyase) and CYP21A2 (P450c21, 21-hydroxylase) are required for the biosynthesis of androgens, glucocorticoids, and mineralocorticoids. Both enzymes hydroxylate progesterone at adjacent, distal carbon atoms and show limited tolerance for substrate modification. Halogenated substrate analogs have been employed for many years to probe cytochrome P450 catalysis and to block sites of reactivity, particularly for potential drugs. Consequently, we developed efficient synthetic approaches to introducing one or more halogen atom to the 17- and 21-positions of progesterone and pregnenolone. In particular, novel 21,21,21-tribromoprogesterone and 21,21,21-trichloroprogesterone were synthesized using the nucleophilic addition of either bromoform or chloroform anion onto an aldehyde precursor as the key step to introduce the trihalomethyl moieties. When incubated with microsomes from yeast expressing human CYP21A2 or CYP17A1 with P450-oxidoreductase, CYP21A2 metabolized 17-fluoroprogesterone to a single product, whereas incubations with CYP17A1 gave no products. Halogenated steroids provide a robust system for exploring the substrate tolerance and catalytic plasticity of human steroid hydroxylases.
[Mh] Termos MeSH primário: Microssomos/enzimologia
Pregnanos/síntese química
Esteroide 17-alfa-Hidroxilase/química
Esteroide 21-Hidroxilase/química
Esteroides Bromados/síntese química
Esteroides Clorados/síntese química
Esteroides Fluorados/síntese química
[Mh] Termos MeSH secundário: Colesterol Oxidase/química
Cromatografia Líquida de Alta Pressão
Ensaios Enzimáticos
Seres Humanos
Microssomos/química
Oxirredução
Pregnanos/química
Proteínas Recombinantes/química
Proteínas Recombinantes/metabolismo
Esteroide 17-alfa-Hidroxilase/metabolismo
Esteroide 21-Hidroxilase/metabolismo
Esteroides Bromados/química
Esteroides Clorados/química
Esteroides Fluorados/química
Especificidade por Substrato
Leveduras
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Pregnanes); 0 (Recombinant Proteins); 0 (Steroids, Brominated); 0 (Steroids, Chlorinated); 0 (Steroids, Fluorinated); EC 1.1.3.6 (Cholesterol Oxidase); EC 1.14.14.16 (CYP21A2 protein, human); EC 1.14.14.16 (Steroid 21-Hydroxylase); EC 1.14.14.19 (CYP17A1 protein, human); EC 1.14.14.19 (Steroid 17-alpha-Hydroxylase)
[Em] Mês de entrada:1202
[Cu] Atualização por classe:170220
[Lr] Data última revisão:
170220
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:111018
[St] Status:MEDLINE
[do] DOI:10.1016/j.jsbmb.2011.09.007


  2 / 29 MEDLINE  
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[PMID]:3455044
[Au] Autor:Fung YK; Stevens JM; Palmer CW; Brueggemeier RW
[Ad] Endereço:Department of Oral Biology, University of Nebraska Medical Center, College of Dentistry, Lincoln 68583.
[Ti] Título:Inhibition by bromoestrogens of the effects of estradiol on apomorphine-induced climbing behavior.
[So] Source:Steroids;49(4-5):287-94, 1987 Apr-May.
[Is] ISSN:0039-128X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The chronic administration of estrogens to mice or rats will result in antidopaminergic effects. Apomorphine-induced climbing behavior in mice, the result of direct stimulation of dopamine receptors in the striatal and mesolimbic regions, is a simple animal model for examining these antidopaminergic effects of estrogens. Bromoestrogens, inhibitors of catechol estrogen formation, have been utilized in order to examine the role of estrogen metabolism in dopaminergic antagonism. Mice were pretreated for 3 days with 2-bromoestradiol, 4-bromoestradiol, or 2,4-dibromoestradiol dibenzoates alone or in combination with estradiol benzoate prior to apomorphine administration. The haloestrogens did not alter the climbing-induced responses elicited by apomorphine, whereas estradiol benzoate clearly attentuated the actions of apomorphine. Furthermore, the bromoestradiol dibenzoates were effective in reversing the effects of estradiol benzoate when the two steroids (estradiol benzoate and a bromoestrogen dibenzoate) were administered simultaneously during pretreatment. Thus, the bromoestrogens are able to inhibit the antidopaminergic effects of estradiol exhibited in the apomorphine-induced mouse climbing model.
[Mh] Termos MeSH primário: Apomorfina/farmacologia
Estradiol/farmacologia
Atividade Motora/efeitos dos fármacos
Esteroides Bromados/farmacologia
[Mh] Termos MeSH secundário: Animais
Antagonistas de Estrogênios
Masculino
Camundongos
Camundongos Endogâmicos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Estrogen Antagonists); 0 (Steroids, Brominated); 4TI98Z838E (Estradiol); N21FAR7B4S (Apomorphine)
[Em] Mês de entrada:8809
[Cu] Atualização por classe:141120
[Lr] Data última revisão:
141120
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:870401
[St] Status:MEDLINE


  3 / 29 MEDLINE  
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[PMID]:3834659
[Au] Autor:Numazawa M; Ogata M; Abiko K; Nagaoka M
[Ti] Título:Stereoselective hydrolysis of 16 alpha-halo-17-keto steroids and long-range substitution effects on the hydrolysis of 16 alpha-bromo-17-ketones and 2 alpha-bromo-3-ketones.
[So] Source:Steroids;45(5):403-10, 1985 May.
[Is] ISSN:0039-128X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Epimerizations of 16 alpha-chloro- (1a), bromo- (1b), and iodo-3 beta-hydroxy-5-androsten-17-one (1c) by a brief treatment with 0.2 equiv NaOH in aqueous pyridine reached equilibrium between 16 alpha- and 16 beta-halo ketones. 16 alpha-/16 beta-Halo ketone ratios at equilibrium were 1.5 for Cl, 1.25 for Br, and 1.0 for I. Kinetic analysis showed that compounds 1a-c were stereoselectively converted to the corresponding 16 alpha-hydroxy derivative 3 by an SN2 mechanism, in which the order of the apparent reactivity was Br greater than I greater than Cl. The hydrolysis of a number of 16 alpha-bromo-17-ketones and 2 alpha-bromo-3-ketones was carried out. The yields of the corresponding alcohols were found to depend on remote structural features in the steroids.
[Mh] Termos MeSH primário: 17-Cetosteroides
Esteroides Bromados
Esteroides Clorados
[Mh] Termos MeSH secundário: Fenômenos Químicos
Química
Hidrólise
Hidróxido de Sódio
Estereoisomerismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (17-Ketosteroids); 0 (Steroids, Brominated); 0 (Steroids, Chlorinated); 55X04QC32I (Sodium Hydroxide)
[Em] Mês de entrada:8606
[Cu] Atualização por classe:131121
[Lr] Data última revisão:
131121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:850501
[St] Status:MEDLINE


  4 / 29 MEDLINE  
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[PMID]:6691970
[Au] Autor:Ziegler K; Frimmer M; Fasold H
[Ti] Título:Further characterization of membrane proteins involved in the transport of organic anions in hepatocytes. Comparison of two different affinity labels: 4,4'-diisothiocyano-1,2-diphenylethane-2,2'-disulfonic acid and brominated taurodehydrocholic acid.
[So] Source:Biochim Biophys Acta;769(1):117-29, 1984 Jan 11.
[Is] ISSN:0006-3002
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:4,4'-Diisothiocyano-1,2-diphenylethane-2,2'-disulfonic acid (H2DIDS) known as an irreversible inhibitor of the anion transport in red blood cells (Cabantchik, Z.I. and Rothstein, A. (1972) J. Membrane Biol. 10, 311-330) blocks also the uptake of bile acids and of some foreign substrates in isolated hepatocytes (Petzinger, E. and Frimmer, M. (1980) Arch. Toxicol. 44, 127-135). [3H]H2DIDS was used for labeling of membrane proteins probably involved in anion transport of rat liver cells. The membrane proteins modified in vitro by [3H]H2DIDS were compared with those labeled by brominated taurodehydrocholic acid. The latter is one of a series of suitable taurocholate derivatives, all able to bind to defined membrane proteins of hepatocytes and also known to block the uptake of bile acids as well as of phallotoxins and of cholecystographic agents (Ziegler, K., Frimmer, M., Möller, W. and Fasold, H. (1982) Naunyn-Schmiedeberg's Arch. Pharmacol. 319, 254-261). The radiolabeled proteins were compared after SDS-electrophoresis with and without reducing agent present, solubilization by detergents, two-dimensional electrophoresis and after separation of integral and peripheral proteins. Our results suggest that the anion transport system of liver cells cannot distinguish between bile acids and the anionic stilbene derivative (DIDS). The labeling pattern for both kinds of affinity labels was very similar. Various combinations of separation techniques gave evidence that the radiolabeled membrane proteins are not subunits of a single native channel protein.
[Mh] Termos MeSH primário: Ácido 4,4´-Di-Isotiocianoestilbeno-2,2´-Dissulfônico/análogos & derivados
Fígado/metabolismo
Proteínas de Membrana/fisiologia
[Mh] Termos MeSH secundário: Ácido 4-Acetamido-4'-isotiocianatostilbeno-2,2'-dissulfônico/análogos & derivados
Marcadores de Afinidade
Animais
Transporte Biológico/efeitos dos fármacos
Dissulfetos
Peso Molecular
Ratos
Esteroides Bromados
Ácido Taurocólico/análogos & derivados
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Affinity Labels); 0 (Disulfides); 0 (Membrane Proteins); 0 (Steroids, Brominated); 27816-59-7 (4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid); 517-37-3 (taurodehydrocholate); 5E090O0G3Z (Taurocholic Acid); 61481-03-6 (dihydro-DIDS); Q1O6DSW23R (4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid)
[Em] Mês de entrada:8403
[Cu] Atualização por classe:161126
[Lr] Data última revisão:
161126
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:840111
[St] Status:MEDLINE


  5 / 29 MEDLINE  
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[PMID]:7090029
[Au] Autor:Numazawa M; Nagaoka M
[Ti] Título:Controlled alkaline hydrolysis of steroidal alpha-bromoketones: new conditions and synthesis of 2 alpha-hydroxy-3-ones.
[So] Source:Steroids;39(3):345-55, 1982 Mar.
[Is] ISSN:0039-128X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Controlled alkaline hydrolysis of 16 alpha-bromo-17-keto steroids 1, 5 and 7 with potassium carbonate and tetra-n-butylammonium hydroxide (n-Bu4NOH) and synthesis of 2 alpha-hydroxy-3-ones 11, 13 and 16 by the controlled hydrolysis of the corresponding 2 alpha-bromo-3-ones 9, 12 and 15 are described. Treatment of the bromoketones 1,5 and 7 with potassium carbonate in aqueous acetone or with n-Bu4NOH in aqueous dimethylformamide (DMF) gave 16 alpha-hydroxy-17-ones 3m 6 and 8 in 85-90% yield, respectively. 2 alpha-Hydroxy-3-ones 11, 13 and 16 were obtained by hydrolysis of the corresponding bromoketones 9, 12 and 15 in high yields using the above conditions or sodium hydroxide in pyridine or DMF, respectively. Deuterium labeling experiments suggested that equilibration between the 2 alpha-bromoketone 9 and the 2 beta-bromo isomer 10 precedes the formation of the ketol 11 in which the true intermediate might be the 2 beta-isomer 10. However, rearranged androstane derivatives, 3 beta-hydroxy-2-one 18 and 20, were stereoselectively obtained by treatment of the bromoketones 12 and 15 with an excess amount of sodium hydroxide.
[Mh] Termos MeSH primário: Hidroxiesteroides/síntese química
Cetosteroides
Esteroides Bromados
[Mh] Termos MeSH secundário: Hidrólise
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Hydroxysteroids); 0 (Ketosteroids); 0 (Steroids, Brominated)
[Em] Mês de entrada:8208
[Cu] Atualização por classe:061115
[Lr] Data última revisão:
061115
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:820301
[St] Status:MEDLINE


  6 / 29 MEDLINE  
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[PMID]:6287311
[Au] Autor:Ziegler K; Frimmer M; Möller W; Fasold H
[Ti] Título:Chemical modification of membrane proteins by brominated taurodehydrocholate in isolated hepatocytes; relationship to the uptake of cholate and of phalloidin and to the sensitivity of hepatocytes to phalloidin.
[So] Source:Naunyn Schmiedebergs Arch Pharmacol;319(3):254-61, 1982 Jun.
[Is] ISSN:0028-1298
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:In vitro treatment of isolated rat hepatocytes with brominated taurodehydrocholic acid (BTC) reduced their sensitivity against phalloidin and inhibited the uptake of phalloidin as well as of cholate in an irreversible and concentration dependent manner. BTC was taken up itself by liver cells; this process was inhibited by 4,4'-diisothiocyano 2,2'-stilbene disulfonate (DIDS). When hepatocytes were incubated with 35S-BTC their plasma membranes contained five labeled protein species with molecular weights of 67,000, 49,000, 38,000, 32,000 and 24,000 as shown by SDS-electrophoresis. No marked difference was observed when isolated plasma membranes from livers were directly treated with the affinity label. DIDS suppressed covalent binding of 35S-BTC to membrane components drastically. Incubation of phalloidin insensitive AS-30D ascites hepatoma cells with 35S-BTC did not result in a chemical modification of the above five proteins. This agrees with an earlier observation that hepatoma cells are unable to take up phalloidin and bile acids (Petzinger et al. 1979; Rufeger and Grundmann 1977; Kroker et al. 1978).
[Mh] Termos MeSH primário: Marcadores de Afinidade/farmacologia
Ácidos Cólicos/metabolismo
Ácido Desoxicólico/análogos & derivados
Fígado/metabolismo
Proteínas de Membrana/metabolismo
Oligopeptídeos/metabolismo
Faloidina/metabolismo
Esteroides Bromados/farmacologia
Ácido Taurodesoxicólico/análogos & derivados
[Mh] Termos MeSH secundário: Marcadores de Afinidade/metabolismo
Animais
Carcinoma Hepatocelular/metabolismo
Técnicas In Vitro
Fígado/efeitos dos fármacos
Neoplasias Hepáticas
Faloidina/farmacologia
Ratos
Radioisótopos de Enxofre
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Affinity Labels); 0 (Cholic Acids); 0 (Membrane Proteins); 0 (Oligopeptides); 0 (Steroids, Brominated); 0 (Sulfur Radioisotopes); 005990WHZZ (Deoxycholic Acid); 17466-45-4 (Phalloidine); 516-50-7 (Taurodeoxycholic Acid)
[Em] Mês de entrada:8210
[Cu] Atualização por classe:170714
[Lr] Data última revisão:
170714
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:820601
[St] Status:MEDLINE


  7 / 29 MEDLINE  
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[PMID]:7222143
[Au] Autor:Jennings BH; Yelle LM
[Ti] Título:The oxidation of a steroidal bromohydrin revisited.
[So] Source:Steroids;37(1):7-22, 1981 Jan.
[Is] ISSN:0039-128X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:A comparative study was made of the reactions of 5-bromo-3 beta, 6 beta-dihydroxy-5 alpha-androstan-17-one 3-acetate (1) with lead tetraacetate alone and in the presence of iodine in both high intensity visible light and in total darkness using a variety of solvents. Markedly different product profiles were obtained under the different reaction conditions, making our results of both practical importance and theoretical interest.
[Mh] Termos MeSH primário: Androstanóis
Compostos Organometálicos
Esteroides Bromados
[Mh] Termos MeSH secundário: Fenômenos Químicos
Química
Iodo
Chumbo
Luz
Espectroscopia de Ressonância Magnética
Oxirredução
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Androstanols); 0 (Organometallic Compounds); 0 (Steroids, Brominated); 2P299V784P (Lead); 4229-69-0 (5-bromo-3,6-dihydroxyandrostan-17-one-3-acetate); 9679TC07X4 (Iodine); CFN24B03DB (lead tetraacetate)
[Em] Mês de entrada:8106
[Cu] Atualização por classe:131121
[Lr] Data última revisão:
131121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:810101
[St] Status:MEDLINE


  8 / 29 MEDLINE  
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[PMID]:6778976
[Au] Autor:Katzenellenbogen JA; Senderoff SG; McElvany KD; O'Brien HA; Welch MJ
[Ti] Título:16 alpha-[77Br]bromoestradiol-17 beta: a high specific-activity, gamma-emitting tracer with uptake in rat uterus and uterus and induced mammary tumors.
[So] Source:J Nucl Med;22(1):42-7, 1981 Jan.
[Is] ISSN:0161-5505
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:16 alpha-[77Br]Bromoestradiol-17 beta (Compound 1) has been synthesized by radiobromination of estrone enoldiacetate. Tissue uptake studies performed 1 hr after administration of Compound 1 to immature or mature female rats showed uterus-to-blood ratios of 13, with nontarget issue-to-blood ratios ranging from 0.6 to 2. Co-administration of unlabelled estradiol caused a selective depression in the uterine uptake with no effect on nontarget tissue uptake. In adult animals bearing adenocarcinomas induced by DMBA (7,12-dimethylbenz(a)anthracene), tumor-to-blood ratios of 6.3 were obtained, this uptake also being depressed in animals treated with unlabeled estradiol. The studies demonstrate that Compound 1 has suitable binding properties and sufficiently high specific activity so that its uptake in estrogen target tissues in vivo is mediated primarily by the estrogen receptor. Furthermore, they suggest that this compound may be suitable for imaging human breast tumors that contain estrogen receptors.
[Mh] Termos MeSH primário: Bromo
Estradiol
Neoplasias Mamárias Experimentais/metabolismo
Esteroides Bromados
Útero/metabolismo
[Mh] Termos MeSH secundário: 9,10-Dimetil-1,2-benzantraceno
Animais
Estradiol/síntese química
Feminino
Neoplasias Mamárias Experimentais/induzido quimicamente
Radioisótopos
Ratos
Receptores Estrogênicos/metabolismo
Esteroides Bromados/síntese química
Distribuição Tecidual
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, U.S. GOV'T, P.H.S.
[Nm] Nome de substância:
0 (Radioisotopes); 0 (Receptors, Estrogen); 0 (Steroids, Brominated); 4TI98Z838E (Estradiol); 57-97-6 (9,10-Dimethyl-1,2-benzanthracene); SBV4XY874G (Bromine)
[Em] Mês de entrada:8103
[Cu] Atualização por classe:151119
[Lr] Data última revisão:
151119
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:810101
[St] Status:MEDLINE


  9 / 29 MEDLINE  
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[PMID]:6457907
[Au] Autor:Abou-Gharbia M; Pashko L; Schwartz A; Swern D
[Ti] Título:Synthesis of dehydroepiandrosterone sulfatide and 16 alpha-halogenated steroids.
[So] Source:J Pharm Sci;70(10):1154-7, 1981 Oct.
[Is] ISSN:0022-3549
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Dehydroepiandrosterone sulfatide was prepared in a 68% yield by the reaction of 5-androstene-3 beta-ol-17-one 3 sulfate (silver salt) with dipalmitoyl alpha-iodopropylene glycol. The sulfatide was found to be a more potent inhibitor of human glucose-6-phosphate dehydrogenase than dehydroepiandrosterone. 16 alpha-Halogenated steroids also were prepared by direct halogenation of the steroid or indirect halogenation of an appropriate steroidal intermediate. Among various halogenated steroids, 16 alpha-bromoepiandrosterone was 50 times as potent as dehydroepiandrosterone as an inhibitor of glucose-6-phosphate dehydrogenase.
[Mh] Termos MeSH primário: Desidroepiandrosterona/análogos & derivados
Esteroides Bromados/síntese química
Sulfoglicoesfingolipídeos/síntese química
[Mh] Termos MeSH secundário: Animais
Desidroepiandrosterona/síntese química
Eritrócitos/enzimologia
Glucosefosfato Desidrogenase/antagonistas & inibidores
Seres Humanos
Camundongos
Esteroides Clorados/síntese química
Esteroides Fluorados/síntese química
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; RESEARCH SUPPORT, U.S. GOV'T, P.H.S.
[Nm] Nome de substância:
0 (Steroids, Brominated); 0 (Steroids, Chlorinated); 0 (Steroids, Fluorinated); 0 (Sulfoglycosphingolipids); 459AG36T1B (Dehydroepiandrosterone); EC 1.1.1.49 (Glucosephosphate Dehydrogenase)
[Em] Mês de entrada:8201
[Cu] Atualização por classe:131121
[Lr] Data última revisão:
131121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:811001
[St] Status:MEDLINE


  10 / 29 MEDLINE  
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[PMID]:6929616
[Au] Autor:Sweet F; Ahmed R; Morgan TE; Sweet BC
[Ti] Título:Bifunctional enzyme activity at the same active site: competitive inhibition kinetics with 3 alpha/20 beta-hydroxysteroid dehydrogenase.
[So] Source:Steroids;35(1):111-8, 1980 Jan.
[Is] ISSN:0039-128X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:20 beta-Hydroxy-5 alpha-pregnan-3-one (HPO) is a competitive inhibitor of reduction by 3 alpha/20 beta-hydroxysteroid dehydrogenase (3 alpha/20 beta-HSD; E.C.1.1.1.53) of 17 beta-hydroxy-5 alpha-androstan-3-one (DHT; 3 alpha-activity; Ki = 4.6x10(-5)M), and of 6 beta-acetoxyprogesterone (6 beta-AP; 20 beta-activity; Ki = 4.34x10(-5)M). HPO and DHT inhibit affinity alkylation of 3 alpha/20 beta-HSD by 6 beta-bromoacetoxyprogesterone (6 beta-BAP). The facts that 1) enzyme 3 alpha-activity and 20 beta-activity are both competitively inhibited by HPO with practically identical Ki-values, 2) 6 beta-BAP is solely a 20 beta-activity substrate for 3 alpha/20 beta-HSD, 3) one mole of 6 beta-BAP reacts with one mole of 3 alpha/20 beta-HSD to simultaneously inactivate 3 alpha- and 20 beta-activity, and 4) inactivation of 3 alpha/20 beta-HSD by 6 beta-BAP is inhibited by DHT (a C19-steroid) or HPO (a C21-steroid), support the view that the same active site of 3 alpha/20 beta-HSD possesses both 3 alpha- and 20 beta-activity. Bifunctional activity at the same active site is considered for other steroid-specific enzymes in female mammalian reproductive systems.
[Mh] Termos MeSH primário: 20-Hidroxiesteroide Desidrogenases/metabolismo
Cortisona Redutase/metabolismo
[Mh] Termos MeSH secundário: Ligação Competitiva
Cortisona/farmacologia
Di-Hidrotestosterona/farmacologia
Hidroxiprogesteronas/farmacologia
Isomerismo
Cinética
Pregnanolona/análogos & derivados
Pregnanolona/farmacologia
Esteroides Bromados/farmacologia
Streptomyces/enzimologia
Relação Estrutura-Atividade
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, U.S. GOV'T, P.H.S.
[Nm] Nome de substância:
0 (6-bromoacetoxyprogesterone); 0 (Hydroxyprogesterones); 0 (Steroids, Brominated); 08J2K08A3Y (Dihydrotestosterone); 1675-95-2 (6 beta-acetoxyprogesterone); 516-59-6 (allopregnan-20 alpha-ol-3-one); BXO86P3XXW (Pregnanolone); EC 1.1.1.- (20-Hydroxysteroid Dehydrogenases); EC 1.1.1.53 (Cortisone Reductase); V27W9254FZ (Cortisone)
[Em] Mês de entrada:8007
[Cu] Atualização por classe:131121
[Lr] Data última revisão:
131121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:800101
[St] Status:MEDLINE



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