SEX STEROID BINDING PLASMA PROTEIN (SBP)

1970 ◽  
Vol 65 (1_Suppl) ◽  
pp. S204-S224 ◽  
Author(s):  
C. Mercier-Bodard ◽  
A. Alfsen ◽  
E. E. Baulieu

ABSTRACT The detection, preparation from plasma Cohn fraction IV and purification of SBP are reported. The association constant has the value of K = 1.2 and 0.5 109 M−1 at 4°C for testosterone and oestradiol, respectively. A preparation homogeneous by the criteria of polyacrylamide gel electrophoresis, binding studies and ultracentrifugation is obtained; sedimentation equilibrium experiments give a molecular weight of approx. 52 000, confirming the approximative value obtained from Sephadex filtration.

1979 ◽  
Vol 11 (1) ◽  
pp. 253-259 ◽  
Author(s):  
Christine Mercier-Bodard ◽  
Jack-Michel Renoir ◽  
Etienne-Emile Baulieu

1980 ◽  
Vol 191 (3) ◽  
pp. 799-809 ◽  
Author(s):  
R G Sutcliffe ◽  
B M Kukulska-Langlands ◽  
J R Coggins ◽  
J B Hunter ◽  
C H Gore

Pregnancy-associated plasma protein-A (PAPP-A) has been purified by a combination of methods including antibody-affinity chromatography. The resultant protein, obtained in 16% yield from maternal serum, appeared as a single major component on non-denaturing polyacrylamide and SDS/polyacrylamide gel electrophoresis. The protein showed a single component when analysed by isoelectric focusing under denaturing conditions in the presence and absence of reduction and had a pI of 4.34 and 4.42 respectively. These pI values were indistinguishable from those of alpha 2-macroglobulin (alpha 2M). The molecular weight of the PAPP-A polypeptide as shown by SDS/polyacrylamide-gel electrophoresis was 187000, with a minor component of mol.wt. 82500 that was attributed to proteolysis. Since native PAPP-A had a molecular weight on gel chromatography very similar to that of alpha 2M (620000–820000), it was concluded that PAPP-A was a homotetramer. In the absence of reduction, a high-molecular-weight (420000) protomer of PAPP-A was found. It was deduced that PAPP-A, like alpha 2M, is a dinner, whose protomers are composed of disulphide-linked polypeptide chains. It was found that the molecular weight of the PAPP-A polypeptide exceeded that of alpha 2M by 3.3%, but that the total carbohydrate content of PAPP-A exceeded that of alpha 2M by 10% and that its neutral carbohydrate content exceeded that of alpha 2M by between 7.4 and 9.0%. The significance of the estimated molecular weights of alpha 2M (181000) and its major tryptic fragments is discussed in the light of published values. A tryptic fragment alpha 2M (82500 mol.wt.) was apparently the same size as the major tryptic fragment of PAPP-A.


1969 ◽  
Vol 115 (4) ◽  
pp. 639-643 ◽  
Author(s):  
R. H. Villet ◽  
K. Dalziel

A method is described for the isolation of 6-phosphogluconate dehydrogenase from sheep liver. The product appears to be homogeneous in polyacrylamide-gel electrophoresis and in sedimentation-velocity and sedimentation-equilibrium studies in the ultracentrifuge. The molecular weight is estimated as 129000 from equilibrium sedimentation.


1984 ◽  
Vol 106 (3) ◽  
pp. 428-432 ◽  
Author(s):  
Yoshiyuki Maruyama ◽  
Norihiko Aoki ◽  
Yasuyuki Suzuki ◽  
Hyogo Sinohara ◽  
Toshio Yamamoto

Abstract. A radioimmunoassay for human sex-steroidbinding plasma protein (SBP) was developed. With this assay, SBP was determined in sera of 138 normal men and 169 non-pregnant women, ranging in age from 11 to 87 years. The results indicate (i) that SBP levels in both sexes increase gradually with age up to mid-eighties, (ii) that the average levels in mid-eighties are approximately twice those in early twenties, and (iii) that the average levels in women are about twice as high as those in men of corresponding age. These results may also account for the discrepancies in the previous papers regarding the normal blood levels and sexual difference of SBP in adult men and women.


Steroids ◽  
1981 ◽  
Vol 37 (4) ◽  
pp. 455-462 ◽  
Author(s):  
M. Egloff ◽  
R. Vranckx ◽  
J. Tardivel-Lacombe ◽  
H. Degrelle

1976 ◽  
Vol 22 (9) ◽  
pp. 1410-1414 ◽  
Author(s):  
George L. Enders Jr. ◽  
Charles L. Duncan

Polyacrylamide gel electrophoresis of highly purified Clostridium perfringens enterotoxin revealed electrophoretic microheterogeneity of the enterotoxin, apparently because of slight charge differences in the peptides. Detergent gel electrophoresis showed that purified enterotoxin formed high molecular weight aggregates in the presence of both sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide. No conditions capable of inhibiting this phenomenon were found. Although a molecular weight of 35 000 daltons has been reported in the literature, the experimentally determined molecular weight values in the presence of detergents corresponded to multiples of a theoretical subunit molecular weight of 17 500 daltons. Binding studies performed by equilibrium dialysis and ultracentrifugation methods revealed that the enterotoxin bound very small amounts of SDS per gram of protein. The evidence presented indicates possible detergent induced structural alterations of the protein.


1981 ◽  
Vol 197 (2) ◽  
pp. 427-436 ◽  
Author(s):  
G A Nimmo ◽  
J R Coggins

Neurospora crassa contains three isoenzymes of 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase, which are inhibited by tyrosine, tryptophan and phenylalanine respectively, and it was estimated that the relative proportions of the total activity were 54%, 14% and 32% respectively. The tryptophan-sensitive isoenzyme was purified to homogeneity as judged by polyacrylamide-gel electrophoresis and ultracentrifugation. The tyrosine-sensitive and phenylalanine-sensitive isoenzymes were only partially purified. The three isoenzymes were completely separated from each other, however, and can be distinguished by (NH4)2SO4 fractionation, chromatography on DEAE-cellulose and Ultrogel AcA-34 and polyacrylamide-gel electrophoresis. Polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate indicated that the tryptophan-sensitive isoenzyme contained one type of subunit of molecular weight 52000. The molecular weight of the native enzyme was found to be 200000 by sedimentation-equilibrium centrifugation, indicating that the enzyme is a tetramer, and the results of cross-linking and gel-filtration studies were in agreement with this conclusion.


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