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Incorporation of nitrotyrosine into alpha-tubulin by recombinant mammalian tubulin-tyrosine ligase.
Kalisz, H M; Erck, C; Plessmann, U; Wehland, J.
Afiliação
  • Kalisz HM; Gesellschaft für Biotechnologische Forschung, Abteilung Zellbiologie, Braunschweig, Germany.
Biochim Biophys Acta ; 1481(1): 131-8, 2000 Aug 31.
Article em En | MEDLINE | ID: mdl-11004583
Tubulin-tyrosine ligase (TTL, EC 6.3.2.25) from porcine brain, which catalyses the readdition of tyrosine to the C-terminus of detyrosinated alpha-tubulin, was cloned and expressed in Escherichia coli as a glutathione S-transferase-fusion protein. Upon cleavage of the immobilised fusion protein, an electrophoretically homogeneous enzyme was obtained. Recombinant TTL, which exhibited similar catalytic properties as the mammalian enzyme purified from brain tissue, was capable of using nitrotyrosine as an alternative substrate in vitro. Incorporation of tyrosine into tubulin was competitively inhibited by nitrotyrosine with an apparent K(i) of 0.24 mM. The TTL-catalysed incorporation of nitrotyrosine as sole substrate into alpha-tubulin was clearly detectable at concentrations of 10 microM by immunological methods using nitrotyrosine specific antibodies. However, in competition with tyrosine 20-fold higher concentrations of nitrotyrosine were necessary before its incorporation became evident. Analysis of the C-terminal peptides of in vitro modified alpha-tubulin by MALDI-MS confirmed the covalent incorporation of nitrotyrosine into tubulin by TTL. In contrast to the C-terminal tyrosine, pancreatic carboxypeptidase A was incapable of cleaving nitrotyrosine from the modified alpha-tubulin.
Assuntos
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Base de dados: MEDLINE Assunto principal: Peptídeo Sintases / Tirosina / Tubulina (Proteína) Limite: Animals Idioma: En Ano de publicação: 2000 Tipo de documento: Article
Buscar no Google
Base de dados: MEDLINE Assunto principal: Peptídeo Sintases / Tirosina / Tubulina (Proteína) Limite: Animals Idioma: En Ano de publicação: 2000 Tipo de documento: Article