Protein tyrosine kinase activity was assayed in a variety of chicken tissues during embryonic development and in the adult. In some tissues protein tyrosine kinase activity decreased during embryonic development; however, in other tissues it remained high throughout development, it contrast to the level of protein tyrosine phosphorylation, which decreased during development. The highest levels ...

1. Rat-liver supernatant preparations are capable of achieving the biological sulphation of l-tyrosine methyl ester, the reaction proceeding maximally at a substrate concentration of 30 mm and at pH 7.0. 2. Two sulphated products are formed, one of which has been identified as l-tyrosine O-sulphate. On the basis of indirect evidence the other product can be assumed to be l-tyrosine O-sulphate m...

The effects of tyrosine on plasma response and cognition in aging are unknown. We assessed the dose-dependent response to tyrosine administration in older adults in both plasma tyrosine concentrations and working memory performance. In this double blind randomized cross-over trial 17 older adults (aged 60-75 years) received a single administration of 100, 150, or 200 mg/kg body weight of tyrosi...

The tyrosine decarboxylase operon of Lactobacillus brevis IOEB9809 contains, adjacent to the tyrosine decarboxylase gene, a gene for TyrP, a putative tyrosine transporter. The two genes potentially form a proton motive tyrosine decarboxylation pathway. The putative tyrosine transporter gene of L. brevis was expressed in Lactococcus lactis and functionally characterized using right-side-out memb...

We reported previously that stimulation of RBL-2H3 cells through the high-affinity IgE receptor resulted in tyrosine phosphorylation of a 72-kDa protein (pp72) that was coupled to signal transduction. In the present study, although pp72 tyrosine phosphorylation was induced only by antigen triggering, stimulation of RBL-2H3 cells by either antigen or the calcium-ionophore A23187 led to increased...

The evolution of multicellular metazoans from a unicellular ancestor is one of the most important advances in the history of life. Protein tyrosine kinases play important roles in cell-to-cell communication, cell adhesion, and differentiation in metazoans; thus, elucidating their origins and early evolution is crucial for understanding the origin of metazoans. Although tyrosine kinases exist in...