The crystalline yolk-platelet proteins and their soluble plasma precursor in an amphibian, Xenopus laevis.
Biochem J
; 124(4): 759-66, 1971 Oct.
Article
em En
| MEDLINE
| ID: mdl-5131731
ABSTRACT
A single lipophosphoprotein complex, vitellogenin, was isolated and purified from the plasma of oestrogen-stimulated female toads by preparative ultracentrifugation and chromatography on TEAE-cellulose (triethylaminoethylcellulose). The protein contains 12% lipid, 1.5% phosphorus, 1.6% calcium and smaller amounts of carbohydrates and biliverdin. In amino acid composition it is identical with total yolk-platelet protein. The platelet protein, however, is fractionated on TEAE-cellulose into two components, a high-molecular-weight lipovitellin and a smaller phosvitin. Analyses of the soluble plasma vitellogenin suggest that it is a complex of two phosvitin molecules covalently bound to one lipovitellin dimer, and that it is the immediate precursor of the yolk proteins, into which it is converted by a molecular rearrangement. Uptake of vitellogenin from the plasma into the growing oocyte, and its subsequent crystallization as a yolk platelet, appear to be enhanced by gonadotrophic hormones.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Ácidos Fosfóricos
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Proteínas
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Embrião não Mamífero
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Lipoproteínas
Idioma:
En
Revista:
Biochem J
Ano de publicação:
1971
Tipo de documento:
Article