NMR analysis of regioselectivity in dephosphorylation of a triphosphotyrosyl dodecapeptide autophosphorylation site of the insulin receptor by a catalytic fragment of LAR phosphotyrosine phosphatase.
Protein Sci
; 1(10): 1353-62, 1992 Oct.
Article
em En
| MEDLINE
| ID: mdl-1303753
ABSTRACT
An autophosphorylation site in the activated insulin receptor tyrosine kinase domain has three tyrosines phosphorylated when fully activated. To begin to examine recognition of triphosphotyrosyl sites by protein tyrosine phosphatases in possible control of signal transduction a triphosphotyrosyl dodecapeptide TRDIpYETDpYpYRK corresponding to residues 1,142-1,153 of the insulin receptor was prepared and incubated with the 40-kDa catalytic domain of the human PTPase LAR. To assess regioselectivity of recognition, the three diphosphotyrosyl regioisomers, and the three monophosphotyrosyl regioisomers were prepared and assayed. All seven peptides were PTPase substrates. To identify any preferences in dephosphorylation at pY5, pY9, or pY10, 1H-NMR analyses were conducted during enzyme incubations and distinguishing fingerprint regions determined for each of the seven phosphotyrosyl peptides. LAR PTPase shows strong preference for dephosphorylation first at pY5 (at tri-, di-, and monophosphotyrosyl levels). Initially this regioselectivity gives the Y5(pY9)(pY10) diphospho regioisomer, followed by equal dephosphorylation at pY9 or pY10 to give the corresponding monophosphoryl species on the way to fully dephosphorylated product. The NMR methodology is applicable to other peptides with multiple sites of phosphorylation that undergo attack by any phosphatase.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tirosina
/
Receptor de Insulina
/
Glicoproteínas
/
Proteínas Tirosina Fosfatases
/
Receptores de Superfície Celular
Idioma:
En
Revista:
Protein Sci
Assunto da revista:
BIOQUIMICA
Ano de publicação:
1992
Tipo de documento:
Article
País de publicação:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA