The nuclear matrix from rat liver is capable of phosphorylating exogenous tyrosine-containing substrates |
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| Authors: | H Teraoka Y Ohmura K Tsukada |
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| Institution: | Department of Pathological Biochemistry, Tokyo Medical and Dental University, Japan. |
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| Abstract: | The nuclear matrix isolated from rat liver phosphorylated exogenous tyrosine-containing substrates angiotensin II and synthetic polymer (Glu, Tyr; 4:1). The phosphorylation reaction was dependent on Mn2+ or Mg2+, but the former was the preferred ion. Km values for poly(Glu,Tyr; 4:1) and ATP were 0.2 mM and 4 microM, respectively. Angiotensin II showed a lower affinity for the kinase than poly(Glu,Tyr; 4:1). The isoflavone genistein, a specific inhibitor for tyrosine phosphorylation, inhibited the tyrosine kinase activity in the nuclear matrix. |
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