Tyrosine protein kinase in boar spermatozoa: identification and partial characterization.
A protein-tyrosine kinase has been isolated from a detergent-soluble extract of boar spermatozoa, using poly(Glu, Tyr)4:1 as a substrate. The purification procedure involves sequential column chromatographies on phosphocellulose, polyamino acid affinity and Sephadex G-100 molecular sieving, and results in more than a 1200-fold enrichment. Analysis of the most purified preparation by sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed a major Coomassie blue-stained band of molecular mass 42 kDa. The Tyr-protein kinase does not seem to be autophosphorylable. The Km value for poly(Glu, Tyr)4:1 is relatively low, 2.3 microM, and the tyrosine-polymer phosphorylating activity is apparently inhibited by tyrphostin. The characteristics shown by this new tyrosine kinase--the first to be described in mature male germ cells--support the hypothesis that it belongs to the group of non-receptor-associated tyrosine kinases.
Berruti
G
G
Department of Biology, University of Milan, Italy.
Porzio
S
S
D000818:Animals; D001345:Autoradiography; D015153:Blotting, Western; D002853:Chromatography, Liquid; D003902:Detergents; D004591:Electrophoresis, Polyacrylamide Gel; D008297:Male; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D013094:Spermatozoa / Q000201:enzymology*; D013379:Substrate Specificity; D013552:Swine
D003902:Detergents; D011505:Protein-Tyrosine Kinases