scholarly journals p-Nitrophenol sulfate conjugation with substrate inhibition in rat liver cytosol fraction.

1983 ◽  
Vol 31 (12) ◽  
pp. 4565-4567 ◽  
Author(s):  
TAKASHI MIZUMA ◽  
HIROYUKI YAMAGUCHI ◽  
MASAHIRO HAYASHI ◽  
SHOJI AWAZU
Keyword(s):  
Rat Liver ◽  
Substrate Inhibition ◽  
Cytosol Fraction ◽  
Liver Cytosol ◽  
Rat Liver Cytosol

Influence of Gonads on the Sulfurylation of 11-Deoxycorticosterone and Corticosterone by Rat Liver Cytosol

1971 ◽  
Vol 49 (4) ◽  
pp. 437-440 ◽  
Author(s):  
J. S. Torday ◽  
G. P. Klein ◽  
C. J. P. Giroud
Keyword(s):  
Body Weight ◽  
Rat Liver ◽  
Cytosol Fraction ◽  
Liver Cytosol ◽  
Daily Dose ◽  
17Β Estradiol ◽  
Rat Liver Cytosol ◽  
Gut Homogenate

When incubated in the presence of ATP, the cytosol fraction of rat liver, kidney, and gut homogenate is capable of sulfurylating 11-deoxycorticosterone, the extent of sulfurylation by liver cytosol being three to four times more efficient in the female than in the male. This sex-linked difference in liver sulfokinase activity is further demonstrated by the finding that sulfurylation of corticosterone is decreased by ovariectomy and brought back to the level observed in normal females by injection of 17β-estradiol (at the daily dose of 6 μg/100 g body weight) to castrated females; this effect is increased by orchidectomy and further enhanced by the administration of the same dose of 17β-estradiol to orchidectomized rats.

scholarly journals Identification and partial purification of a unique phenolic steroid sulphotransferase in rat liver cytosol

1984 ◽  
Vol 224 (3) ◽  
pp. 947-953 ◽  
Author(s):  
Y Sugiyama ◽  
A Stolz ◽  
M Sugimoto ◽  
J Kuhlenkamp ◽  
T Yamada ◽  
...  
Keyword(s):  
Rat Liver ◽  
Organic Anion ◽  
Substrate Inhibition ◽  
Gel Filtration ◽  
Male Rat ◽  
Partial Purification ◽  
Ph Optimum ◽  
Liver Cytosol ◽  
Bile Acid Binding ◽  
Rat Liver Cytosol

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.

scholarly journals Reduction of ubiquinone in membrane lipids by rat liver cytosol and its involvement in the cellular defence system against lipid peroxidation

1995 ◽  
Vol 309 (3) ◽  
pp. 883-890 ◽  
Author(s):  
T Takahashi ◽  
T Yamaguchi ◽  
M Shitashige ◽  
T Okamoto ◽  
T Kishi
Keyword(s):  
Lipid Peroxidation ◽  
Rat Liver ◽  
Membrane Lipids ◽  
Reductase Activity ◽  
Egg Yolk ◽  
Cytosol Fraction ◽  
Liver Cytosol ◽  
Intracellular Fraction ◽  
Endogenous Antioxidant ◽  
Rat Liver Cytosol

Rat liver homogenates reduced ubiquinone (UQ)-10 to ubiquinol (UQH2)-10 in the presence of NADPH rather than NADH. This NADPH-dependent UQ reductase (NADPH-UQ reductase) activity that was not inhibited by antimycin A and rotenone, was located mainly in the cytosol fraction and its activity accounted for 68% of that of the homogenates. Furthermore, the NADPH-UQ reductase from rat liver cytosol efficiently reduced both UQ-10 incorporated into egg yolk lecithin liposomes, and native UQ-9 residing in rat microsomes, to the respective UQH2 form in the presence of NADPH. The gross redox ratios of UQH2-9/(UQ-9 + UQH2-9) in individual tissues of rat correlated positively with the log of their respective cytosolic NADPH-UQ reductase activities, while the redox ratios in every intracellular fraction from liver were at about the same level, irrespective of NADPH-UQ reductase activities in the respective fractions. The combined addition of rat liver cytosol and NADPH inhibited to a great extent 2,2′-azobis(2,4-dimethyl-valeronitrile)-induced lipid peroxidation of UQ-10-fortified lecithin liposomes and completely inhibited such peroxidation in the liposomes in which UQH2-10 replaced UQ-10. The NADPH-UQ reductase activity was clearly separated from DT-diaphorase (EC 1.6.99.2) activity by means of Cibacron Blue-immobilized Bio-Gel A-5m chromatography. In conclusion, the NADPH-UQ reductase in cytosol, which is a novel enzyme to our knowledge, was presumed to be responsible for maintaining the steady-state redox levels of intracellular UQ and thereby to act as an endogenous antioxidant in protecting intracellular membranes from lipid peroxidation that is inevitably induced in aerobic metabolism.

scholarly journals Purification and characterization of rat liver minoxidil sulphotransferase

1990 ◽  
Vol 270 (3) ◽  
pp. 721-728 ◽  
Author(s):  
S J Hirshey ◽  
C N Falany
Keyword(s):  
Molecular Mass ◽  
Rat Liver ◽  
Substrate Inhibition ◽  
Active Form ◽  
Structural Similarity ◽  
Liver Cytosol ◽  
Low Concentrations ◽  
Exclusion Chromatography ◽  
A Subunit ◽  
Rat Liver Cytosol

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.

scholarly journals Alterations in translatable messenger RNA coding for phosphoenolpyruvate carboxykinase (GTP) in rat liver cytosol during deinduction.

1978 ◽  
Vol 253 (12) ◽  
pp. 4327-4332
Author(s):  
D. Kioussis ◽  
L. Reshef ◽  
H. Cohen ◽  
S.M. Tilghman ◽  
P.B. Iynedjian ◽  
...  
Keyword(s):  
Rat Liver ◽  
Messenger Rna ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Liver Cytosol ◽  
Rat Liver Cytosol

scholarly journals Transformation of the glucocorticoid receptor in rat liver cytosol by lysosomal enzymes.

1979 ◽  
Vol 254 (5) ◽  
pp. 1537-1539 ◽  
Author(s):  
J. Carlstedt-Duke ◽  
O. Wrange ◽  
E. Dahlberg ◽  
J.A. Gustafsson ◽  
B. Högberg
Keyword(s):  
Glucocorticoid Receptor ◽  
Rat Liver ◽  
Lysosomal Enzymes ◽  
Liver Cytosol ◽  
Rat Liver Cytosol
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