Purification and immunochemical characterization of a male-specific rat liver oestrogen sulphotransferase.
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ABSTRACT:
SUBMITTER: Borthwick EB
PROVIDER: S-EPMC1132234 | biostudies-other | 1993 Feb
REPOSITORIES: biostudies-other
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Project description:Minoxidil (Mx), a pyrimidine N-oxide, is used therapeutically as an antihypertensive agent and to induce hair growth in patients with male pattern baldness. Mx NO-sulphate has been implicated as the agent active in producing these effects. This paper describes the purification of a unique sulphotransferase (ST) from rat liver cytosol that is capable of catalysing the sulphation of Mx. By using DEAE-Sepharose CL-6B chromatography, hydroxyapatite chromatography and ATP-agarose affinity chromatography, Mx-ST activity was purified 240-fold compared with the activity in cytosol. The purified enzyme was also capable of sulphating p-nitrophenol (PNP) at low concentrations (less than 10 microM). Mx-ST was purified to homogeneity, as evaluated by SDS/PAGE and reverse-phase h.p.l.c. The active form of the enzyme had a molecular mass of 66,000-68,000 Da as estimated by gel exclusion chromatography and a subunit molecular mass of 35,000 Da. The apparent Km values for Mx, 3'-phosphoadenosine 5'-phosphosulphate and PNP were 625 microM, 5.0 microM and 0.5 microM respectively. However, PNP displayed potent substrate inhibition at concentrations above 1.2 microM. Antibodies raised in rabbits to the pure enzyme detected a single band in rat liver cytosol with a subunit molecular mass of 35,000 Da, as determined by immunoblotting. The anti-(rat Mx-ST) antibodies also reacted with the phenol-sulphating form of human liver phenol sulphotransferase, suggesting some structural similarity between these proteins.
| S-EPMC1131791 | biostudies-other
Project description:1. Monoamine oxidase from rat and human liver was purified to homogeneity by the criterion of polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate. 2. The enzyme activity was extracted from mitochondrial preparations by Triton X-100. The enzyme was purified by (NH4)2SO4 fractionation followed by chromatography on DEAE-cellulose, Sepharose 6B, spheroidal hydroxyapatite, and finally chromatography on diazo-coupled tyramine-Sepharose. 3. Distinct differences occur in the chromatographic behaviour of the two enzymes on both DEAE-cellulose and spheroidal hydroxyapatite. 4. It is unlikely that the purification of the enzymes on tyramine-Sepharose is due to affinity chromatography and reasons for this are discussed. 5. The purified enzymes did not oxidize-5-hydroxytryptamine and the relative activities of the enzymes with benzylamine were increased approx. 1.25-fold compared with the enzyme activities of mitochondrial preparations. 6. Immunotitration of enzyme activity in extracts of mitochondrial preparations from rat liver was carried out with 5-hydroxytryptamine, tyramine and benzylamine. The enzyme activities were completely immunoprecipitated by the same volume of antiserum. Similar results were obtained with the antiserum to the enzyme from human liver.
| S-EPMC1164485 | biostudies-other
Project description:A form of sulphotransferase capable of sulphating dehydroepiandrosterone and other steroids was purified from cytosol prepared from human liver. Dehydroepiandrosterone sulphotransferase was purified 621-fold when compared with the activity in cytosol using DEAE-Sepharose CL-6B and adenosine 3',5'-bisphosphate-agarose affinity chromatography. During affinity chromatography, dehydroepiandrosterone sulphation activity could be resolved from p-nitrophenol sulphation activity catalysed by phenol sulphotransferase by using a gradient of adenosine 3'-phosphate 5'-phosphosulphate. The purified enzyme was most active towards dehydroepiandrosterone but was capable of conjugating a number of other steroids, including pregnenolone, androsterone and beta-oestradiol. No activity towards p-nitrophenol or dopamine, substrates for the phenol sulphotransferase, was observed with the pure enzyme. A single band with a subunit molecular mass of 35 kDa was observed by Coomassie Blue staining following SDS/polyacrylamide-gel electrophoresis of the purified enzyme. A molecular mass of 68-70 kDa was calculated for the active form of the enzyme by chromatography on Sephacryl S-200, suggesting that the active form of the enzyme is a dimer.
| S-EPMC1138726 | biostudies-other
Project description:BackgroundSteroid sulphatase (STS) is one of the steroid-metabolising enzymes involved in desulphating inactive steroid sulphates and oestrogen sulphotransferase (EST) sulphates active oestrogen. The roles of both STS and EST have not been examined in oestrogen-dependent non-small-cell lung cancer (NSCLC).MethodsWe evaluated the immunoreactivity of STS and EST in NSCLC cases using immunohistochemistry. The function of STS and EST was further demonstrated using NSCLC cell lines.ResultsThe immunoreactivity of STS and EST was detected in 49.5% and 27.8% of NSCLC cases, respectively. The immunoreactivity of STS was significantly higher in female adenocarcinoma cases. The STS-positive NSCLCs were also significantly correlated in an inversed manner with tumour size and cell proliferation and tended to be associated with better clinical outcome. However, the immunoreactivity of EST was significantly correlated with intracellular oestradiol concentration. Results of in vitro analysis demonstrated that oestrone sulphate (E1-S) induced and pregnenolone sulphate (Preg-S) inhibited the proliferation in STS-expressing cell lines. The inhibition by Preg-S was reversed by a specific progesterone receptor blocker. Simultaneous addition of E1-S and Preg-S significantly suppressed the proliferation.ConclusionIn NSCLC patients, STS is considered a good prognostic factor. Results of our present study also indicated the benefits of potential progesterone therapy for NSCLC patients.
| S-EPMC3629433 | biostudies-literature
Project description:The endogenous oestrogens have important biological functions in men as well as in women. Because 17beta-oestradiol and oestrone are also formed in the male body, these aromatic oestrogens are generally thought to be responsible for exerting the required oestrogenic functions in the male. In the present study, we tested the hypothesis that some of the non-aromatic steroids that are androgen precursors or metabolites with hydroxyl groups at C-3 and/or C-17 positions may also be able to serve as ligands for the oestrogen receptors (ER) in the male.A total of sixty non-aromatic steroids (selected from families of androstens, androstans, androstadiens, oestrens and oestrans) were analysed for their ability to bind and activate the human ERalpha and ERbetain vitro and in cultured cells.Six of the non-aromatic steroids, that is, 5-androsten-3beta,17beta-diol, 5alpha-androstan-3beta,17beta-diol, 5(10)-oestren-3alpha,17beta-diol, 5(10)-oestren-3beta,17beta-diol, 4-oestren-3beta,17beta-diol and 5alpha-oestran-3beta,17beta-diol, were found to have physiologically relevant high binding affinity ( approximately 50% of that of oestrone) for human ERalpha and ERbeta. These non-aromatic steroids also activated the transcriptional activity of human ERs and elicited biological responses (such as growth stimulation) in two representative ER-positive human cancer cell lines (MCF-7 and LNCaP) with physiologically relevant potency and efficacy. Molecular docking analysis of these six active compounds showed that they could bind to ERalpha and ERbeta in a manner similar to that of 17beta-oestradiol.These results provide evidence for the possibility that some of the endogenous androgen precursors or metabolites could serve as male-specific ER ligands.
| S-EPMC2801221 | biostudies-literature
Project description:Phenolic steroid sulphotransferase activity for both oestradiol and oestrone was identified in male rat liver cytosol in the 30 000-40 000 Mr fractions on gel filtration when activity was assayed at pH 5.5 (pH optimum 5.5-6.0). Activity for oestradiol but not oestrone was found in the 60 000-70 000-Mr range when assayed at pH 8.0 (pH optimum biphasic, 5.5-6.0 and 7.0-8.0). Km for oestradiol (1.3 microM) was lower than published values for hydroxysteroid sulphotransferases (15-35 microM) and previously reported oestradiol sulphotransferases (71-85 microM). At above 2 microM-oestradiol phenolic sulphotransferase activity exhibited substrate inhibition. The phenolic steroid sulphotransferase activity was found to be distinct in chromatofocusing from organic-anion-binding and bile acid-binding proteins previously identified in this Mr range. Further purification on hydroxyapatite yielded a 44-fold enriched fraction that contained two monomeric bands, Mr 32 500 and 29 500.
| S-EPMC1144532 | biostudies-other
Project description:An oestrogen sulphotransferase, active towards both oestrone and oestradiol, and of high specific activity, is present in cytosol prepared from adrenal glands of both sexes of English Shorthair and Hartley guinea pigs. The ovarian and testicular cytosolic activities of this enzyme are markedly low in comparison with the adrenal activity. The adrenal enzyme is distinct from an accompanying pregnenolone sulphotransferase as judged by f.p.l.c. gel filtration, chromatofocusing, and differences in activation brought about by the addition of thiol groups. The oestrogen sulphotransferase behaved as a 67 kDa protein on a Sephadex G100 column and as a 48 kDa protein on f.p.l.c. gel-filtration columns. Two forms of the enzyme with apparent pI values of 6.1 and 5.5 were eluted during f.p.l.c. chromatofocusing. Sequential salt fractionation, f.p.l.c. gel filtration and elution from an agarose-hexane-adenosine-3',5'-diphosphate affinity gel has resulted in a preparation which, when resubmitted to f.p.l.c. gel filtration, yields a considerably purified oestrogen sulphotransferase. When submitted to SDS/polyacrylamide-gel electrophoresis under reducing conditions, a main protein band of 34-36 kDa is observed. It is suggested that the enzyme may exist as a dimer in the cytosol.
| S-EPMC1131505 | biostudies-other
Project description:1. Rat liver glycosylasparaginase [N4-(beta-N-acetylglucosaminyl)-L-asparaginase, EC 3.5.1.26] was purified to homogeneity by using salt fractionation, CM-cellulose and DEAE-cellulose chromatography, gel filtration on Ultrogel AcA-54, concanavalin A-Sepharose affinity chromatography, heat treatment at 70 degrees C and preparative SDS/polyacrylamide-gel electrophoresis. The purified enzyme had a specific activity of 3.8 mumol of N-acetylglucosamine/min per mg with N4-(beta-N-acetylglucosaminyl)-L-asparagine as substrate. 2. The native enzyme had a molecular mass of 49 kDa and was composed of two non-identical subunits joined by strong non-covalent forces and having molecular masses of 24 and 20 kDa as determined by SDS/polyacrylamide-gel electrophoresis. 3. The 20 kDa subunit contained one high-mannose-type oligosaccharide chain, and the 24 kDa subunit had one high-mannose-type and one complex-type oligosaccharide chain. 4. N-Terminal sequence analysis of each subunit revealed a frayed N-terminus of the 24 kDa subunit and an apparent N-glycosylation of Asn-15 in the same subunit. 5. The enzyme exhibited a broad pH maximum above 7. Two major isoelectric forms were found at pH 6.4 and 6.6. 6. Glycosylasparaginase was stable at 75 degrees C and in 5% (w/v) SDS at pH 7.0.
| S-EPMC1138631 | biostudies-other
Project description:Malate synthase (EC 4.1.3.2) from dark-grown Euglena gracilis was purified to homogeneity by the criterion of polyacrylamide-gel electrophoresis. The enzyme was released from acetate-grown cells by treatment with ultrasonic waves and purified from broken-cell suspensions by high-speed centrifugation and (NH4)2SO4 fractionation, followed by gel-filtration on Sepharose 6B. The final enzyme preparation was purified 190-fold compared with the crude extract. The mol.wt. of the enzyme was about 350000 as determined by gel filtration on Sepharose 6B. Treatment with sodium dodecyl sulphate and urea dissociated the enzyme into subunits of mol.wt. 175000. The pH optimum for the enzyme was 8.0 and the Km values for glyoxylate and acetyl-CoA were 50 and 80 micron respectively. Antibodies raised to the purified enzyme were shown to be monospecific by radiochemical immunoassay. Euglena anti-(malate synthase) tested on Ouchterlony double-diffusion gels gave a sharp precipitation band against acetate-grown Escherichia coli, but no immunological correspondence was observed with acetate-grown Chlorella fusca, Zea mays (maize) scutella or purified malate synthase from Ricinus communis.
| S-EPMC1185753 | biostudies-other
Project description:Rat liver pI-6.4 esterase was purified from microsomes (microsomal extracts) and used to generate antibodies in the rabbit. Two active enzyme forms, similarly sensitive to endo-H (endo-beta-N-acetylglucosaminidase H (EC 3.2.1.96), but differing slightly in polypeptide chain length, were present in the preparation. In microsomes, immunoblots revealed a single form, with Mr congruent to 62,000, identical with the large component of the purified enzyme, indicating that the second component is an artefact. Rabbit reticulocyte lysates and wheat germ extracts programmed with RNA extracted from total or bound polysomes synthesized a single immunoreactive 61 kDa polypeptide, which was not formed with RNA extracted from free polysomes. The immunoreactive product synthesized in the presence of dog pancreas microsomes was slightly larger (62 kDa); like the authentic enzyme, it bound to concanavalin A and was decreased in molecular size to 60 kDa by the action of endo-H. Thus the enzyme is synthesized with a short cleavable sequence and bears at least one high-mannose oligosaccharide chain. Metabolic labelling in hepatocytes cultured with [35S]methionine also generated a single immunoreactive polypeptide of 62 kDa, which was decreased to 60 kDa in size by treatment with endo-H or addition of tunicamycin to the culture medium. This confirms the molecular homogeneity and the glycosylation of the enzyme in the intact cell. Culture media contained no pI-6.4-esterase-related protein, whether tunicamycin was present or not. The processing steps in the synthesis of pI-6.4 esterase are thus, as for other esterases of the endoplasmic reticulum [Robbi & Beaufay (1986) Eur. J. Biochem. 158, 187-194; (1987) Biochem. J. 248, 545-550] indistinguishable from those occurring early in the synthesis of secretory proteins. Glycosylation is apparently not the sorting signal responsible for their retention in the endoplasmic reticulum.
| S-EPMC1135038 | biostudies-other