AMINO-ACID-COMPOSITION AND ENDOCRINE CONTROL OF VITELLINE ENVELOPE PROTEINS IN EUROPEAN SEA BASS (DICENTRARCHUS-LABRAX) AND GILTHEAD SEA BREAM (SPARUS-AURATA)

The vitelline envelopes of European sea bass and gilthead sea bream ar e both composed of mainly four proteins with the molecular masses of 9 0, 52, 48, 45 kDa and 75, 50, 48, 44 kDa, respectively. Each protein h as an amino acid composition that is characterized by a high content o f proline and glutamic acid and a low content of cysteine, similar to the whole vitelline envelope of both species. The amino acid compositi on suggests that each protein is distinct but related to the other vit elline envelope proteins. The use of homologous antisera shows that bo th species have vitelline envelope proteins that are induced by estrad iol-17 beta. As males of both species synthesize these proteins after treatment with estradiol-17 beta, the origin is not restricted to the ovaries. Vitellogenin of both Eurpoean sea bass and gilthead sea bream has the apparent molecular mass of 170 kDa. (C) 1995 Wiley-Liss, Inc.