Partial purification of a tyrosine kinase activity associated with a 28-kDa phosphoprotein from the particulate fraction of rat spleen.
A phosphoprotein with associated tyrosine kinase activity has been purified from a 26,000 x g particulate fraction of rat spleen. The molecular weight of the native kinase is 85-90 kDa as estimated by gel permeation chromatography on Superdex 200 while SDS/PAGE of an autophosphorylated sample indicated a single 28-kDa band in which the radiolabel was alkali-stable. The SDS/PAGE following the incubation with 5'-p-fluorosulfonylbenzoyl[8-14C]adenosine reveals a single labeled band migrating at a molecular weight of approximately 28 kDa. The enzyme shows very restricted substrate specificity. Casein and, to a lesser degree, the random polypeptide poly(Tyr1,Glu4) were phosphorylated. The enzyme exhibits a preference for Mn2+ over Mg2+ as an activator.
Borowski
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P
Institute for Medical Microbiology and Immunology, University of Eppendorf, Hamburg, Germany.
Medem
S
S
Laufs
R
R
D000241:Adenosine / Q000031:analogs & derivatives / Q000378:metabolism; D000345:Affinity Labels / Q000378:metabolism; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002458:Cell Fractionation; D002845:Chromatography; D002846:Chromatography, Affinity; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D017886:Durapatite; D004591:Electrophoresis, Polyacrylamide Gel; D006882:Hydroxyapatites; D007700:Kinetics; D008970:Molecular Weight; D010750:Phosphoproteins / Q000302:isolation & purification* / Q000378:metabolism; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000302:isolation & purification* / Q000378:metabolism; D051381:Rats; D013154:Spleen / Q000201:enzymology*; D013347:Subcellular Fractions / Q000201:enzymology
D000345:Affinity Labels; D000596:Amino Acids; D006882:Hydroxyapatites; D010750:Phosphoproteins; C010959:5'-(4-fluorosulfonylbenzoyl)adenosine; D017886:Durapatite; D011505:Protein-Tyrosine Kinases; D000241:Adenosine