Identification of a new in vitro substrate of tyrosine protein kinase

• Published in: Biochemistry (Easton) Vol. 26; no. 17; pp. 5226 - 5229
• Main Authors: Tokuda, Masaaki, Kong, Siow Kee, Khanna, Navin C, Waisman, David Morton
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 25.08.1987
• Subjects: Amino Acids - analysis; Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Brain; Cattle; Enzymes and enzyme inhibitors; Fundamental and applied biological sciences. Psychology; Kinetics; Phosphorylation; Protein-Tyrosine Kinases - isolation & purification; Protein-Tyrosine Kinases - metabolism; spleen; Spleen - enzymology; Substrate Specificity; Transferases; Spleen; Binding protein; Vertebrata; Phosphorylation; Mammalia; Rat; Enzyme; Substrate specificity; Rodentia; Calcium Ions; Protein-tyrosine kinase
• ISSN: 0006-2960; 1520-4995
• DOI: 10.1021/bi00391a002

Recent studies in our laboratory [Tokuda, M., Khanna, N.C., Aurora, A., & Waisman, D. M. (1986) Biochem. Biophys. Res. Commun. 139, 910-917] have identified in membranes of rat spleen two tyrosine protein kinases named TPK-I and TPK-II. In this paper the identification of the Ca2+ binding protein CAB-48 as a major in vitro substrate of TPK-II is reported. TPK-II catalyzed the incorporation of 0.73 mol of phosphate/mol of CAB-48. Phosphoamino acid analysis revealed that phosphorylation of CAB-48 was specific for tyrosine residues. Phosphorylation of CAB-48 by TPK-I (rat spleen), protein kinase C, casein kinase I, casein kinase II, cAMP-dependent protein kinase, or calcium calmodulin dependent protein kinase was not observed.