Description
ZAP70 is a non-receptor protein tyrosine kinase (part of the Syk/Zap70 family) that is involved in signaling by the T-cell antigen receptor (TCR). Ligation of the TCR/CD3 receptor in Jurkat T-cells induces phosphoprotein complexes which contain ZAP70 (1). TCR zeta chains are initially phosphorylated by p56Lck that lead to the recruitment of ZAP70 via its SH2 domain. ZAP70 in turn phosphorylates other proteins in the TCR-phosphoprotein complex. ZAP70 tyrosine kinase is tyrosine phosphorylated in Jurkat T cells and in purified peripheral T cells after MHC-I ligation. The phosphorylation of ZAP70 after MHC-I ligation is dependent on TCR/CD3 surface expression. One of the natural substrates for ZAP70 is the zeta-chain dimer of the TCR/CD3 complex (2). Another substrate of ZAP70 is LAT (linker for activation of T cells). Direct tyrosine phosphorylation of LAT with activated protein-tyrosine kinase Zap70 is necessary and sufficient for the association and activation of signalling proteins. Zap-70 efficiently phosphorylates LAT on tyrosine residues at positions 226, 191, 171, 132 and 127. By substituting these tyrosine residues in LAT with phenylalanine and by utilizing phosphorylated peptides derived from these sites, the tyrosine residues in LAT have been shown to be required for the direct interaction and activation of Vav, p85/p110 and phospholipase C1 (PLC1) (3).
Biomolecule/Target: N/A
Synonyms: ZAP70, zeta-chain (TCR) associated protein kinase 70kDa
Alternates names: ZAP70, zeta-chain (TCR) associated protein kinase 70kDa, Syk-related tyrosine kinase
Taglines: Involved in signaling by the T-cell antigen receptor
NCBI Gene ID #: 3952
NCBI Gene Symbol: LEP
Gene Source: N/A
Accession #: P41159
Recombinant: Yes
Source: Baculovirus (Sf9 insect cells)
Purity by SDS-PAGEs: 98%
Assay: SDS-PAGE
Purity: N/A
Assay #2: HPLC
Endotoxin Level: N/A
Activity (Specifications/test method): 113 nmol phosphate incorporated into Poly(Glu-Tyr) substrate per minute per mg protein at 30°C for 15 minutes using a final concentration of 50 µM ATP (0.83 µCi/assay in 25µl reaction volume).
Biological activity: s human Leptin has been shown to be biologically active in two different mouse obesity models, ob/ob and NZO. Both strains of mice were treated via intraperitoneal injection once daily at a dose of 5 mg Leptin/gm of body weight for 7 days. Significant effects on body weight, food consumption, and plasma glucose levels were observed to saline-treated controls.
Results: N/A
Binding Capacity: N/A
Unit Definition: N/A
Molecular Weight: 16.0 kDa
Concentration: 5µg/50 µl
Appearance: Liquid
Physical form description: Recombinant proteins in storage buffer (50 mM Tris-HCl, pH 7.5, 150 mM NaCl, 0.25 mM DTT, 0.1 mM EGTA, 0.1 mM EDTA, 0.1 mM PMSF, 25% glycerol).
Reconstitution Instructions: Add 15 mM sterile HCl (0.5 ml/1 mg vial or 5 ml/10 mg vial) to the vial. After the protein is completely dissolved, add 7.5 mM sterile NaOH (0.3 ml/1 mg vial or 3 ml/10 mg vial) to bring the pH to approximately 5.2.
Amino acid sequence: N/A