Tyrosine, III

The biosynthetic pathway for MDP chromophore involves the production of (i) aminosugar previously named madurose (ii) p-hydroxyacid (S)-3-(2-chloro-3-hydro xy-4-methoxyphenyl)-3-hydroxypropionic acid derived from L-a-tyrosine (iii) 6-methylsalicyl-CoA and (iv) enediyne portion and a convergent biosynthetic approach to the final MDP chromophore. 

Fig. 3. N-tosyl L-tyrosine (III) ORD curves in function of the pH and of the excess potassium...

Fig. 10. ORD curves of polycondensates of N-tosyl L-tyrosine (III) with HCHO prepared in acidic medium (IX) with different initial proportion of HCHO (solvent dioxanne)...

III. Tyr protein kinases A. Cytosolic tyrosine kinases src, fgr, abl, etc.) B. Receptor tyrosine kinases (RTKs) Plasma membrane receptors for hormones such as epidermal growth factor (EGF) or platelet-derived growth factor (PDGE) Raf (a protein kinase)... 

Though a large number of small molecule inhibitors against a variety of tyrosine kinases are being developed, the most advanced drugs can be roughly classified as (i) Bcr-Abl/Src family kinase inhibitors, (ii) ErbB inhibitors and (iii) broad spectrum TfCIs with an anti-angiogenic component. 

In order to test the tissue compatibility of tyrosine-derived poly-(iminocarbonates), solvent cast films of poIy(CTTH) were subcutaneously implanted into the back of outbread mice. In this study, conventional poly(L-tyrosine) served as a control (42). With only small variations, the experimental protocol described for the biocompatibility testing of poly(N-palmitoylhydroxyproline ester) (Sec. III. 

Kentolysin Compared to Heliantholysin. Stoichactis helianthus occurs in the Caribbean region whereas another species, Stoichactis kenti is distributed in the Indo-Pacific area. The latter produces a toxin, kentolysin, that is similar to, but not identical with heliantholysin (6). The amino acid compositions of the two polypeptides show a distinct resemblance but appear to differ significantly in number of residues of lysine, methionine, tyrosine and histidine. IgG from a rabbit immunized against heliantholysin neutralizes both heliantholysin and kentolysin, but neutralization of the homologous toxin is more efficient (Table III). It can be seen that in the concentrations used, the IgG failed to neutralize the related lytic peptides of Condylactis gigantea and Epiactis prolifera. 

Table III. BPDE-Induced Mutations at the Three TAC Tyrosine Codons...

Figure 28.21 The reactions of R u (11) pby 3 + are catalyzed by light at 452 nm that begins by forming an excited state intermediate. In the presence of persulfate, a sulfate radical is formed concomitant with the oxidative product Ru(III)bpy33+. This form of the chelate is able to catalyze the formation of a radical on a tyrosine phenolic ring that can react along with the sulfate radical either with a nucleophile, such as a cysteine thiol, or with another tyrosine side chain to form a covalent linkage. The result of this reaction cascade is to cause protein crosslinks to form when a sample containing these components is irradiated with light.

III Receptors with intrinsic tyrosine kinase activity... 

Figure 1.5. Newman projections about the C —bond, showing the possible positions of the phenol group (R) in relation to the C substituents. The rotamer assignments I, II, and III and the corresponding values of the torsion angle Xi are indicated for tyrosine (and its derivatives) of the l configuration.

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