Document Detail


Isolation of two forms of rat alpha-fetoprotein and comparison of their binding parameters with estradiol-17beta.
MedLine Citation:
PMID:  53073     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In polyacrylamide gels, highly purified rat alpha1-fetoprotein shows a molecular heterogeneity, i.e. a "slow" and a "fast" moving fraction. We have isolated by electrophoretic fractionation and subsequent elution these two forms of alpha1-fetoprotein, and we have studied comparatively the binding parameters for estradiol-17beta of whole alpha1-fetoprotein preparations and of the isolated forms. We have shown that the number of binding sites per molecule of whole alpha1-fetoprotein is always, in our experimental conditions, a fractional number, inferior to unity (0.3). Furthermore, the analysis of the binding parameters of the "two forms" of alpha1-fetoprotein allows discrimination between different classes of binding sites. For the "slow" fraction, the number of predominant binding sites per molecule of protein is close to unity (0.7-0.9), whereas for the "fast" fraction, a very low fractional value is found (0.1). The corresponding association constants are reproducibly different for the two fractions: Ka = 0.1.10(8) M-1 for the "slow" alpha1-fetoprotein, and Ka = 0.7.10(8) M-1 for the "fast" alpha1-fetoprotein. Traces of a very high affinity (10(9) M-1) minor class of binding sites are demonstrated in the "slow" fraction. These results point to the existence of a molecular population of alpha1-fetoprotein, some forms of which have a strong or very strong affinity, and some a negligible affinity, for estrogens.
Authors:
C Benassayag; G Vallette; N Cittanova; E Nunez; M F Jayle
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Biochimica et biophysica acta     Volume:  412     ISSN:  0006-3002     ISO Abbreviation:  Biochim. Biophys. Acta     Publication Date:  1975 Dec 
Date Detail:
Created Date:  1976-02-09     Completed Date:  1976-02-09     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0217513     Medline TA:  Biochim Biophys Acta     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  295-305     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Binding Sites
Carcinoma, Hepatocellular / blood
Estradiol*
Female
Fetal Proteins*
Liver Neoplasms / blood
Male
Protein Binding
Protein Conformation
Rats
alpha-Fetoproteins* / immunology,  isolation & purification
Chemical
Reg. No./Substance:
0/Fetal Proteins; 0/alpha-Fetoproteins; 50-28-2/Estradiol

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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