scholarly journals Androgen-sensitive spermine-binding protein of rat ventral prostate. Purification of the protein and characterization of the hormonal effect

1979 ◽  
Vol 184 (2) ◽  
pp. 431-440 ◽  
Author(s):  
G Mezzetti ◽  
R Loor ◽  
S Liao
Keyword(s):  
Binding Protein ◽  
Sodium Dodecyl ◽  
Deae Cellulose ◽  
Binding Activity ◽  
Ventral Prostate ◽  
Hormonal Effect ◽  
Rat Ventral Prostate ◽  
Acidic Fraction ◽  
Androgen Effect

The rat ventral prostate contains a cytosol protein that can non-covalently bind spermine much more tightly than spermidine or other natural diamines. The protein has been purified to homogeneity, as judged by electrophoresis in urea- and sodium dodecyl sulphate-containing polyacrylamide gels. The protein, with or without spermine bound to it, sediments at 3 S in a sucrose gradient with or without 0.4 M-KCl. The molecular weight of the protein is about 30 000. Each molecule of the binding protein can bind one molecule of spermine. In the prostate of rats injected with cycloheximide, the protein appears to have a half-life of about 3.5 h. The spermine-binding activity of an acidic fraction obtained by DEAE-cellulose chromatography of the prostate cytosol proteins is reduced by about 40–60% within 20–40 h after castration. This effect is reversed very rapidly within 15–30 min by intraperitoneal injection of 5 alpha-dihydrotestosterone. The hormonal effect is androgen-specific and is not mimicked by dexamethasone or oestradiol-17 beta. The androgen effect was reduced significantly when rats were injected with cycloheximide or actinomycin D, suggesting that the acidic protein may be one of the earliest proteins induced by androgen in the rat ventral prostate.

scholarly journals Characterization of colchicine-binding activity in Dictyostelium discoideum

1978 ◽  
Vol 169 (3) ◽  
pp. 499-504 ◽  
Author(s):  
P Cappuccinelli ◽  
B D Hames
Keyword(s):  
Dictyostelium Discoideum ◽  
High Speed ◽  
Binding Protein ◽  
Deae Cellulose ◽  
Binding Activity ◽  
Saturation Kinetics ◽  
Filter Assay ◽  
Kinetics Of ◽  
High Speed Supernatant

A colchicine-binding component was detected in vegetative amoebae of Dictyostelium discoideum by using a Millipore-filter assay. The colchicine-binding activity is temperature-and time-dependent, maximum binding occurring at 22-35 degrees C after 60 min incubation. Further increases in temperature are without effect on the extent of binding, but bound colchicine is released with increased time of incubation. Furthermore, colchicine-binding activity itself decreased in the high-speed supernatant from D. discoideum, with half the activity being lost in approx. 2.5h. Several lines of evidence, including the saturation kinetics of colchicine binding, enhancement of colchicine binding by tartrate, insensitivity to lumicolchicine, precipitation of the binding protein by vinblastine and behaviour of the binding protein on DEAE-cellulose and Sephadex resins, suggest that the colchicine-binding protein may be tubulin.

scholarly journals Immunochemical characterization of the androgen-dependent spermine-binding protein of the rat ventral prostate

1984 ◽  
Vol 218 (2) ◽  
pp. 563-571 ◽  
Author(s):  
R A Hiipakka ◽  
C Chen ◽  
K Schilling ◽  
A Oberhauser ◽  
A Saltzman ◽  
...  
Keyword(s):  
Solid Phase ◽  
Binding Protein ◽  
Deae Cellulose ◽  
Ventral Prostate ◽  
Rat Tissues ◽  
Secretory Product ◽  
Prostatic Fluid ◽  
Rat Ventral Prostate ◽  
Significant Difference

A solid-phase radioimmunoassay was developed to measure the level of the androgen-dependent spermine-binding protein (SBP) in the cytosol fraction of the rat ventral prostate during endocrine manipulation. The concentration of SBP and immunologically cross-reacting material (CRM) in the ventral prostate was at least 5000 times higher than the level of CRM detected in rat serum or cytosol from other rat tissues. Cytosol from the ventral prostate of intact rats was separated by DEAE-cellulose chromatography into three major fractions of CRM. One of these fractions corresponded to the elution position of SBP. Cytosol prepared from rats 48 h after castration lacked SBP and one of the two other fractions of CRM. This loss coincided with an increase in CRM in the remaining fraction. No significant difference was detected in the total level of CRM when intact and 48 h-castrated rats were compared. Injection of rats with 5 alpha-dihydrotestosterone (DHT) immediately after castration prevented these changes in the profile of CRM. Several proteins cross-reacting with antibodies to purified SBP were detected in cytosol by using an immunoblot procedure. The highest-Mr band corresponded to SBP. The effect of short- and long-term castration and subsequent DHT treatment on CRM was studied by using the immunoblot technique. Short-term castration (2 days) led to the disappearance of CRM coinciding with SBP (Mr 35 000-38 000) and an increase in smaller forms of CRM (Mr 24 000 and 22 000). Injection of rats with DHT 2 days after castration led to the reappearance of CRM corresponding to SBP, which returned to normal levels within 4 to 5 days of treatment. Long-term castration (up to 14 days) led to a gradual disappearance of all CRM; subsequent DHT treatment led to the reappearance of all forms of CRM and normal levels were attained within 5 days. We have identified SBP and the various forms of CRM as a secretory product of the rat ventral prostate by immunohistochemical staining and by DEAE-cellulose fractionation of prostatic fluid. Prostatic fluid is rich in proteolytic activity and these proteinases may be responsible for processing SBP to small forms of CRM.

scholarly journals Testosterone regulates the synthesis of major proteins in rat ventral prostate

1978 ◽  
Vol 170 (1) ◽  
pp. 115-121 ◽  
Author(s):  
M G Parker ◽  
G T Scrace ◽  
W I P Mainwaring
Keyword(s):  
Protein Synthesis ◽  
Cyproterone Acetate ◽  
Sodium Dodecyl ◽  
Ventral Prostate ◽  
Cytosol Fraction ◽  
Rat Ventral Prostate ◽  
General Protein Synthesis ◽  
Alpha Beta ◽  
General Protein

The presence of three major proteins alpha, beta and gamma in rat ventral prostate was demonstrated by electrophoresis in polyacrylamide gels containing sodium dodecyl sulphate. Their regulation by androgens was studied by measuring the rates of synthesis of the proteins in minced prostatic tissue by using L-[35S]methionine. The three proteins account for 30-40% of the proteins synthesized in the gland. After castration, their rates of synthesis rapidly decline to about 1% that of normal animals, and this cannot be accounted for by the accompanying decrease in general protein synthesis. Testosterone reverses these changes in castrated animals, so that after 4 days normal synthesis is restored. The regulation is specific for androgens, since cyproterone acetate, an anti-androgen, is inhibitory and oestradiol-17beta and corticosterone are without effect. Preliminary characterization of the proteins indicates that protein alpha (mol.wt. 22000, pI unknown) is a glycoprotein containing glucose and/or mannose residues and occurs in both the mitochondrial and cytosol fractions. Protein beta (mol.wt. 12000, pI5.4) is also a glycoprotein, but is found exclusively in the cytosol fraction. Protein gamma (mol.wt. 8000, pI5.4) is also a glycoprotein, but is found exclusively in the cytosol fraction. Protein gamma (mol.wt. 8000, pI5.4) is also found exclusively in the cytosol fraction.

Partial purification and characterization of a membrane-associated steroid-binding protein from Pseudomonas testosteroni

1982 ◽  
Vol 60 (8) ◽  
pp. 798-803 ◽  
Author(s):  
Mike Francis ◽  
Mamoru Watanabe
Keyword(s):  
Binding Protein ◽  
Membrane Vesicles ◽  
Activity Analysis ◽  
Binding Activity ◽  
Regulatory Function ◽  
Partial Purification ◽  
Purification And Characterization ◽  
Steroid Binding ◽  
Steroid Binding Protein

A steroid-binding protein obtained from the supernatant of the final wash from the preparation of membrane vesicles was purified severalfold to near homogeneity. The protein binds C18 and C19 steroids but has the highest affinity for androstenedione (Kd = 1.6 × 10−10 M). The molecular weight is 51 000 – 58 000. Binding activity is slightly inhibited by Cu2+, Ca2+, and Mg2+ and completely inhibited by Zn2+. The protein has no detectable steroid degradative activity. Analysis of androstenedione binding revealed negative cooperativity of binding for this ligand and may indicate a regulatory function for this protein. It is postulated that this protein binds the steroid after testosterone is converted to androstenedione.

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