scholarly journals Photoaffinity labelling of steroid-hormone-binding glutathione S-transferases with [3H]methyltrienolone. Inhibition of steroid-binding activity by the anticarcinogen indole-3-carbinol

1992 ◽  
Vol 288 (2) ◽  
pp. 361-367 ◽  
Author(s):  
D P Danger ◽  
W S Baldwin ◽  
G A LeBlanc
Keyword(s):  
Mouse Liver ◽  
Steroid Hormone ◽  
Binding Activity ◽  
Untreated Mouse ◽  
Hormone Binding ◽  
Photoaffinity Labelling ◽  
Liver Cytosol ◽  
Glutathione S Transferases ◽  
Steroid Binding

The identification and characterization of steroid-hormone-binding glutathione S-transferases (GST) were undertaken using photoaffinity-labelling techniques. Irradiation of mouse liver cytosol, in the presence of 50 nM-[3H]methyltrienolone, resulted in the specific affinity labelling of five proteins. One of these proteins, designated MBP27, had an approximate molecular mass of 27 kDa under denaturing conditions and was induced by treatment of mice with either 2(3)-t-butyl-4-hydroxyanisole (BHA) or phenobarbital (PB). An additional affinity-labelled protein, MBP25, which was not detected in untreated mouse cytosol, was induced in the liver cytosols from BHA- and PB-treated mice. The molecular masses of these proteins and their induction by BHA and PB suggested that they may be steroid-hormone-binding GST subunits. Irradiation of mouse liver cytosol in the presence of [3H]methyltrienolone, followed by immunoprecipitation using GST-specific antibodies established that both GST mu and GST alpha bind [3H]methyltrienolone and both contribute to the affinity-labelled protein designated MBP27. GST Ya1 Ya1, an alpha class GST that is not expressed in untreated mouse liver but is induced by BHA and PB, was also found to bind [3H]methyltrienolone and is identical with the affinity-labelled protein designated MBP25. Experiments were undertaken next to assess the effects of the anticarcinogenic plant compound indole-3-carbinol (I3C) on GST-mediated steroid hormone-binding using the photoaffinity labelling techniques. Treatment of mice with I3C resulted in the induction of immunoreactive GST mu and GST Ya1 Ya1. However, the steroid-binding activity of these proteins in vitro was severely inhibited by the acid-condensation products of I3C that are generated in the stomach after ingestion. These results suggest that I3C may inhibit GST-mediated steroid-binding activity which could contribute to the anticarcinogenic activity of this compound.

scholarly journals A study of the structures of the YaYa and YaYc glutathione S-transferases from rat liver cytosol Evidence that the Ya monomer is responsible for lithocholate-binding activity

1981 ◽  
Vol 197 (2) ◽  
pp. 491-502 ◽  
Author(s):  
J D Hayes ◽  
R C Strange ◽  
I W Percy-Robb
Keyword(s):  
Rat Liver ◽  
Lithocholic Acid ◽  
Binding Activity ◽  
Glutathione S Transferase ◽  
Liver Cytosol ◽  
Molecular Weights ◽  
Tryptic Digest ◽  
Glutathione S Transferases ◽  
Limited Digestion ◽  
Rat Liver Cytosol

The two dimeric lithocholic acid-binding proteins previously identified as ligandin (YaYa) and glutathione S-transferase B (YaYc) were isolated from rat liver cytosol. These proteins have molecular weights of 44000 and 47000 respectively. The recovery of these two proteins from liver was not affected by the addition of the proteinase inhibitor Trasylol. No spontaneous interconversion between these two proteins was observed on storage. YaYa and YaYc proteins yielded peptides of identical molecular weight after limited digestion with Staphylococcus aureus V8 proteinase. Analytical and preparative tryptic-digest peptide ‘maps’ showed that all the soluble peptides obtained from YaYa protein were also recovered from YaYc protein. Approximately six extra soluble peptides, which were not recovered from YaYa protein, were obtained from the tryptic digest of YaYc protein. Subdigests of the insoluble tryptic-digest ‘cores’ also resulted in the recovery of identical peptides from both proteins. Evidence is presented that the Ya subunit possessed by both proteins is identical; glutathione S transferase B is a hybrid of ligandin and glutathione S-transferase AA. The Ya monomer is responsible for lithocholate binding.

scholarly journals Cholic acid binding by glutathione S-transferases from rat liver cytosol

1980 ◽  
Vol 185 (1) ◽  
pp. 83-87 ◽  
Author(s):  
J D Hayes ◽  
R C Strange ◽  
I W Percy-Robb
Keyword(s):  
Bile Acid ◽  
Cholic Acid ◽  
Reduced Glutathione ◽  
Binding Activity ◽  
Transferase Activity ◽  
Glutathione S Transferase ◽  
Liver Cytosol ◽  
Glutathione S Transferases ◽  
Rat Livers ◽  
Rat Liver Cytosol

Cholic acid-binding activity in cytosol from rat livers appears to be mainly associated with enzymes having glutathione S-transferase activity; at least four of the enzymes in this group can bind the bile acid. Examination of the subunit compositions of different glutathione S-transferases indicated that cholic acid binding and the ability to conjugate reduced glutathione with 1,2-dichloro-4-nitrobenzene may be ascribed to different subunits.

Sex-hormone-binding globulin in human follicular fluid and serum at the time of oocyte recovery

1989 ◽  
Vol 1 (4) ◽  
pp. 289 ◽  
Author(s):  
SM Campo ◽  
PA Rogers ◽  
JK Findlay
Keyword(s):  
Follicular Fluid ◽  
Binding Activity ◽  
Sex Hormone ◽  
Sex Hormone Binding Globulin ◽  
Hormone Binding ◽  
Human Follicular Fluid ◽  
Fertilization Program ◽  
Vitro Fertilization ◽  
Oocyte Recovery

Androgen binding activity, indistinguishable from sex-hormone-binding globulin (SHBG) in serum, has been identified in human follicular fluid by binding analyses (saturation and Scatchard analyses and binding specificity), immunoradiometric assay and Con-A Sepharose chromatography. Follicular fluid was obtained at the time of oocyte recovery from either individual follicles (range 2-7) from seven patients, or as a pool obtained from follicles of several patients who had received a Clomid-human menopausal gonadotrophin treatment to stimulate follicular growth as part of an in vitro fertilization program. Concentrations of SHBG in follicular fluid varied between individual follicles (750 +/- 202 fmol mg-1 protein; mean +/- s.d.; n = 14) and ranged above and below concentrations of SHBG in serum (948 +/- 171 fmol mg-1 protein; n = 5) taken 4 h before oocyte recovery and harvest of follicular fluid. There were strong correlations (r = 0.7-0.9) between the steroid and SHBG contents in individual follicular fluids of two patients. However, the concentration of SHBG in follicular fluid was generally 100-fold lower than that of oestradiol or progesterone, suggesting that SHBG may play some role other than determining the concentration of unbound steroid in the follicle.

STEROID HORMONE METABOLISM IN RESPONSIVE TISSUES IN VITRO

1971 ◽  
Vol 68 (1_Suppl) ◽  
pp. S279-S294 ◽  
Author(s):  
Paul Robel
Keyword(s):  
Steroid Hormone ◽  
Physiological Activity ◽  
Physiological State ◽  
Target Cells ◽  
Target Tissue ◽  
Hormone Metabolism ◽  
Metabolizing Enzymes ◽  
Relationship Of

ABSTRACT Of the information available on steroid hormone metabolism in responsive tissues, only that relating hormone metabolism to physiological activity is reviewed, i. e. metabolite activity in isolated in vitro systems, binding of metabolites to target tissue receptors, specific steroid hormone metabolizing enzymes and relationship of hormone metabolism to target organ physiological state. Further, evidence is presented in the androgen field, demonstrating 5α-reduced metabolites, formed inside the target cells, as active compounds. This has led to a consideration of testosterone as a »prehormone«. The possibility that similar events take place in tissues responding to progesterone is discussed. Finally, the role of hormone metabolism in the regulation of hormone availability and/or renewal in target cells is discussed. In this context, reference is made to the potential role of plasma binding proteins and cytosol receptors.

In vitro binding activity between HCK SH3 domain and HIV-1 Nef protein

2011 ◽  
Vol 31 (3) ◽  
pp. 262-265
Author(s):  
Xiao-lin QIN ◽  
Chao-qi LIU ◽  
Dong-ming REN ◽  
Yong-qin ZHOU
Keyword(s):  
Sh3 Domain ◽  
Binding Activity ◽  
Hiv 1
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