Purification and characterization of a possible protooncogene fjln product, P59fyn, from a rat brain particulate fraction

Takahiro Miyauchi, Masahiro Ariki, Hirofumi Usui, Kentaro Semba, Yumiko Matsuzawa, Tadashi Yamamoto, Kumao Toyoshima, Masao Takeda

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Four tyrosine-protein kinases that reacted with antibodies specific to p62c-yes, p60c-src, p60c-src, and p59fyn, respectively, were solubilized from a rat brain particulate fraction and separated by casein-Toyopearl column chromatography. Possible p59fyn, with a pI of 6.5, was purified 490-fold as a single 69-kDa protein band on SDS-PAGE. The purified enzyme contained almost no phosphotyrosine residues but was autophosphorylated with Mg2+-·ATP exclusively at tyrosine residues, with a concomitant increase in the kinase activity toward tyrosine-glutamate (1 : 4) copolymers. The rate of the copolymer phosphorylation was proportional to the square of the enzyme concentration, suggesting activation through intermolecular catalysis. In the presence of Mn2+, however, the reaction showed a firstorder dependence on the enzyme concentration.

Original languageEnglish
Pages (from-to)729-732
Number of pages4
JournalJournal of biochemistry
Volume112
Issue number6
DOIs
Publication statusPublished - 1992 Dec

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology

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