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Biochemical Properties of the Protein Tyrosine Kinase of the Bacterium Acinetobacter johnsonii
Author(s) -
Grangeasse C.,
Vincent C.,
Doublet P.,
Cozzone A. J.,
Duclos B.
Publication year - 1999
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/713803508
Subject(s) - enzyme , biochemistry , phosphorylation , kinase , biology , protein kinase a , tyrosine , tyrosine phosphorylation , tyrosine kinase , chemistry , signal transduction
The biochemical properties of the autophosphorylating protein tyrosine kinase of Acinetobacter johnsonii were analyzed in vitro. The study shows that the optimal pH value for the phosphorylation reaction is 7. The enzyme activity is stimulated by magnesium and, to a lesser extent, by manganese ions, whereas calcium ions have no effect. The phosphorylation process is rapid reaching a maximum in <2 min, and the enzyme is modified at multiple sites. Interestingly, the bacterial enzyme is insensitive to a series of molecules known to affect the activity of eukaryotic protein tyrosine kinases: genistein, quercetin, tosyllysine chloromethyl ketone, and vanadate. We concluded that, even though the overall phosphorylation reaction catalyzed by the A. johnsonii enzyme is identical to that occurring in eukaryotes, this bacterial kinase exhibits a number of specific properties and therefore probably belongs to a separate group in the general family of protein tyrosine kinases.