title: Characterization of tyrosyl kinase activity in human serum.
abstract: Tyrosyl kinase activity was detected in 1.0 microliter or less of human serum with the substrates angiotensin II, polyamino acid polymer Glu-Tyr (4:1), anti-pp60src IgG, and endogenous serum proteins. Most (about 84%) of the tyrosyl kinase activity was in the 100,000 X g soluble fraction from serum and a similar level of activity was found in the soluble fraction from plasma. Expression of tyrosyl kinase activity in individual serum samples differed more than 15-fold. The different levels of tyrosyl kinase activity were not likely due to phosphatases, proteases, ATPases, or kinase inhibitors and activators in serum. The normal serum and plasma tyrosyl kinase activities were not stimulated by epidermal growth factor, platelet-derived growth factor, insulin, or growth factors from fetal calf serum. Investigations of samples from patients with malignant disorders indicated that those with malignant melanoma contained the highest levels of serum tyrosyl kinase activity.
authors.forename: M F
authors.initials: MF
authors.lastname: Lin
authors.forename: P L
authors.initials: PL
authors.lastname: Lee
authors.forename: G M
authors.initials: GM
authors.lastname: Clinton
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000804:Angiotensin II / Q000378:metabolism; D000818:Animals; D010450:Endopeptidases / Q000097:blood; D004815:Epidermal Growth Factor / Q000494:pharmacology; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D007328:Insulin / Q000494:pharmacology; D036341:Intercellular Signaling Peptides and Proteins; D009369:Neoplasms / Q000201:enzymology; D015688:Oncogene Protein pp60(v-src); D010455:Peptides / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000097:blood; D010750:Phosphoproteins / Q000097:blood; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011494:Protein Kinases / Q000097:blood* / Q000302:isolation & purification; D011505:Protein-Tyrosine Kinases; D011817:Rabbits; D014764:Viral Proteins / Q000276:immunology
chemical_list: D007074:Immunoglobulin G; D007328:Insulin; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D010750:Phosphoproteins; D010982:Platelet-Derived Growth Factor; D014764:Viral Proteins; D000804:Angiotensin II; C027606:L-glutamic acid-L-tyrosine copolymer; D004815:Epidermal Growth Factor; D000255:Adenosine Triphosphate; D011494:Protein Kinases; D011505:Protein-Tyrosine Kinases; D015688:Oncogene Protein pp60(v-src); D010749:Phosphoprotein Phosphatases; D010450:Endopeptidases