Identification of a tyrosine residue in ovine placental lactogen as essential for its binding to receptors.
Biochim Biophys Acta
; 1294(1): 31-6, 1996 May 02.
Article
em En
| MEDLINE
| ID: mdl-8639711
Nitration of ovine placental lactogen (oPL) with a 10-fold molar excess of tetranitromethane over protein content resulted in the modification of 0.8 tyrosine residue. No conformational changes were observed by either fourth-derivative spectral analysis or circular dichroism. Nitration significantly decreased the binding capacity of the hormone to lactogenic and somatogenic rat liver receptors. This binding capacity was not restored by reduction of the nitro groups, thus indicating that the decrease was not due to the difference in pK between tyrosine and nitrotyrosine. The nitrotyrosine-containing peptide was isolated from a tryptic digest by HPLC and its modification extent was of 67%, which is consistent with the decrease in binding capacities (65% and 70%). Its amino acid sequence was determined and the modified tyrosine residue was identified as Tyr-46. These results provide the first evidence of the involvement of a tyrosine residue in the binding of oPL to both lactogenic and somatogenic receptors. This tyrosine appears to be a shared binding epitope between oPL and the prolactins.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Lactogênio Placentário
/
Tirosina
/
Receptores da Somatotropina
/
Receptores de Peptídeos
Tipo de estudo:
Diagnostic_studies
Limite:
Animals
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
1996
Tipo de documento:
Article
País de afiliação:
Argentina
País de publicação:
Holanda