title: Purification and characterization of a possible protooncogene fyn product, p59fyn, from a rat brain particulate fraction.
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 59-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 first-order dependence on the enzyme concentration.
authors.affiliation: Department of Biochemistry, Hiroshima University School of Medicine.
authors.forename: T
authors.initials: T
authors.lastname: Miyauchi
authors.forename: M
authors.initials: M
authors.lastname: Ariki
authors.forename: H
authors.initials: H
authors.lastname: Usui
authors.forename: K
authors.initials: K
authors.lastname: Semba
authors.forename: Y
authors.initials: Y
authors.lastname: Matsuzawa
authors.forename: T
authors.initials: T
authors.lastname: Yamamoto
authors.forename: K
authors.initials: K
authors.lastname: Toyoshima
authors.forename: M
authors.initials: M
authors.lastname: Takeda
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology*; D002845:Chromatography; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D017886:Durapatite; D004591:Electrophoresis, Polyacrylamide Gel; D006882:Hydroxyapatites; D007700:Kinetics; D008297:Male; D008970:Molecular Weight; D011505:Protein-Tyrosine Kinases / Q000302:isolation & purification* / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000302:isolation & purification* / Q000378:metabolism*; D051076:Proto-Oncogene Proteins c-fyn; D011519:Proto-Oncogenes; D051381:Rats; D017208:Rats, Wistar; D013347:Subcellular Fractions / Q000201:enzymology
chemical_list: D006882:Hydroxyapatites; D011518:Proto-Oncogene Proteins; D017886:Durapatite; D011505:Protein-Tyrosine Kinases; C494961:Fyn protein, rat; D051076:Proto-Oncogene Proteins c-fyn