Tyrosine-containing proteins

Each bead can iodinate up to 500 pg of tyrosine-containing protein or peptide. This translates into an oxidative capacity of about 0.55 pmol per bead. The rate of reaction can be controlled by changing the number of beads that are used and altering the sodium iodide concentration added to the reaction. Reaction volumes of 100-1,000 pi are possible per bead. The following protocol is suggested for iodinating proteins. Optimization should be done to determine the best incorporation level to obtain good radiolabel incorporation with retention of protein activity. 

The oxidation of tyrosine-containing proteins and peptides in the presence of tyrosinase has been studied by several workers.47,48 Yasunobu et al. differentiated between the three possible oxidative... 

The phenols and cresols observed on the pyrochromatogram could arise from tyrosine-containing proteins, which yield phenol and p-cresol (17, 21) during pyrolysis. However, because of (1) the similarity in concentration of m- and p-cresol and (2) the low p-cresol/phenol ratio found here (—0.1 expressed as the ratio of the peak areas) compared with the higher values observed with natural proteins such as bovine serum albumin (BSA) (2i) for which this ratio was close to 1, it is more likely that these phenolic peaks originated from polyhydroxyaromatic compounds. 

Human alveolar epithelial cells (A549) and human lung microvascular endothelial cells cultured under hyperoxia (95% O2) + NO (derived from chemical donors) died after 4 to 5 days, whereas cells neither died nor divides in NO alone (Na-RULA et al. 1998). The toxic effect was clearly synergistic, and cell death did not occur via apoptosis. As an indicator of peroxynitrite formation, nitro-tyrosine-containing proteins at molecular masses of 25 and 35 kDa were found to be increased in A549 cells exposed to NO or NO + hyperoxia. 

The reaction of tyrosine or tyrosine-containing proteins with mercuric nitrate to produce a red colour. It can be used to detect tyrosine in urine as in tyrosinosis. 

Skubitz, K. M., Mendiola, J. R., and Collett, M. S. 1988. CD15 monoclonal antibodies react with a phospho-tyrosine-containing protein on the surface of human neutrophils. J Immunol. 141 4318-23. 

PTB domains recognize small peptides containing a phosphotyrosine, usually with the consensus sequence, NPXpY. Some PTB-containing proteins, such as Numb, are able to bind to the consensus peptide in the absence of phosphorylated tyrosine, suggesting phosphotyrosine is dispensable for the function of certain PTB domains. Hydrophobic residues N-termi-nal to the phosphotyrosine provide some specificity of target and distinction from SH2 domains. PTB domains appear to be particularly important in docking... 

Noncatalytic phosphotyrosine binding (PTB) domains are 100-150 residue modules, which bind Asn-Pro-X-Tyr motifs. PTB-domain binding specificity is determined by residues at the amino-terminal side of the phosphotyrosine. In most cases, the tyrosine residue must be phosphorylated in order to mediate binding. PTB domain containing proteins are often found in signal transduction pathways. 

IL-10 inhibits CD28 and ICOS costimulations of T 127 cells via Src homology 2 domain-containing protein tyrosine phosphatase 1. J Allergy Chn Immunol 2007 120 76-83. 

Perret D, Shields M, Saxon A, Kehry MR A mouse Fey Fee protein that inhibits mast cells through activation of FcyRIIB, SH2 domain-containing inositol SS phosphatase 1, and SH2 domain-containing protein tyrosine phosphatases. J Allergy Chn Immunol 2008 121 441-447. 

RECEPTORS CONTAINING PROTEIN TYROSINE KINASES 8.2.1 Cross-Linking of Receptors Causes Activation... 

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