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Partial purification and characterization of cytosolic Tyr-protein kinase(s) from human erythrocytes.
- Source :
- European Journal of Biochemistry; 8/15/88, Vol. 175 Issue 3, p673-678, 6p
- Publication Year :
- 1988
-
Abstract
- Tyrosine-protein kinase, phosphorylating tyrosine residues of transmembrane band 3 protein, has been partially purified from human erythrocyte cytosol by DEAE-Sepharose chromatography followed by heparinSepharose chromatography. Such a Tyr-protein kinase (36 kDa), as distinct from the Ser/Thre-protein kinases (casein kinase S and TS), appears to display a broader site specificity than does the previously described human erythrocyte P-Tyr-protein phosphatase, dephosphorylating band 3 protein. That is, it is able to phosphorylate not only the highly acidic copolymer poly(Glu-Tyr)<subscript>4:1</subscript> but also angiotensin II, lacking an acidic amino acid sequence around the target Tyr residue. Moreover, the phosphorylation of these two substrates exhibits a different pH dependence and a different response to NaC1 and 2,3-bisphosphoglycerate. These results suggest that in intact erythrocytes the cytosolic Tyr-protein kinase might phosphorylate band 3 not only on Tyr-8, surrounded by several acidic side-chains (as demonstrated preferentially to occur in isolated ghosts), but also on other Tyr residues surrounded by other amino acid sequences. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00142956
- Volume :
- 175
- Issue :
- 3
- Database :
- Complementary Index
- Journal :
- European Journal of Biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 13791881
- Full Text :
- https://doi.org/10.1111/j.1432-1033.1988.tb14243.x