Tyrosinamide

P. B. Contino and W. R. Laws, Rotamer-specific fluorescence quenching in tyrosinamide Dynamic and static interactions, J. Fluorescence 1, 5-13 (1991). 

Fig. 4 IPA (dashed line) and 2PA (solid line) spectra, and two-photon polarization ratio, (light dotted line) for phenylalanine, tyrosinamide, tryptophan. The abscissa corresponds to the excitation wavelength of the 2PA case. The IPA spectra are plotted at twice their excitation wavelength. The molecular structures are shown as insets in each graph. Reproduced with permission from [42]. 1993, Elsevier...

Km values for several enzyme-substrate pairs are given in table 7.1. The values vary over a wide range but typically lie between 1CT6 and 10 1 m. With enzymes that can act on several different substrates, Km can vary substantially from substrate to substrate. With the enzyme chymo-trypsin, for example, the Km for the substrate glycyl-tyrosinamide is about 50 times that for the substrate A-benzoyltyrosinamide. 

The retention of the ionized compound is predominately dictated by the uptake of the reagent and the resulting charge on the surface of the column. Figure 4-44 [119] shows the variation of the retention factor of tyrosinamide as a function of the alkylsulfates in the mobile phase. 

Figure 4-44. Capacity factor of tyrosinamide versus concentrations of dodecyl sulfate (upper curve), decyl sulfate (middle curve), and octyl sulfate (lower curve). (Reprinted from reference 119, with permission.)...

C11H1202 6-methoxy-2-tetralone 2472-22-2 23.57 1.0695 2 22075 C11H14N203 N-acetyl-L-tyrosinamide 1948-71-6 25.00 1.1934 2... 

Life as we know it would be impossible without the astonishing characteristics of enzymic catalysis. This catalysis is not only highly efficient, so that reactions may proceed at low temperature and at neutral pH with the speed required by living cells, but it exhibits also a remarkable specificity. Let us cite two typical examples First, the enzyme urease catalyzes the hydrolysis of urea but of no other compound (1). Second, the catalytic action is frequently restricted to one of the antipodes of optically active substrates. Thus, chymotrypsin will catalyze the hydrolysis of acylated L-tyrosinamides, but will not catalyze the reaction of the corresponding derivatives of D-tyrosine (2). 

The dramatic increases in reaction rates that occur in enzyme-catalyzed reactions can be seen for representative systems in the data given in Table 2.2.4 The hydrolysis of the representative amide benzamide by acid or base yields second-order rate constants that are over six orders of magnitude lower than that measured for ben-zoyl-L-tyrosinamide in the presence of the enzyme a-chymotrypsin. An even more dramatic rate enhancement is observed for the hydrolysis of urea The acid-catalyzed hydrolysis is nearly 13 orders of magnitude slower than hydrolysis with the enzyme urease. The disprotionation of hydrogen peroxide into water and molecular oxygen is enhanced by a factor of 1 million in the presence of catalase. 

A different type of peptide hydrolase, dipeptide transferase, catalyzed the oligomerization of dipeptide amides. In the case of glycyl-L-tyrosinamide, the corresponding oligomer with DP up to 8 was formed.242... 

Duncan R, Cable HC, Rejmanove P, et al. Tyrosinamide residues enhance pinocytic capture of N-(2-hydroxypropyl)methacrylamide copolymers. Biochim Biophys Acta 1984 799 1-8. 

Vianini, E., Palumbo, M., Gatto, B. (2001). In vitro selection of DNA aptamers that bind L-tyrosinamide. Bioorg Med Chem 9, 2543-2548. 

Dihydroxy-L-tyrosyl-3,5-dihydroxy-A -[2-(3,4,5-trihydroxyphenyl)ethenyl]-L -tyrosinamide, see T-20254... 

A study of copolymers of N-(2-hydroxypropyl)methacrylamide modified by different amounts of tyrosinamide has shown diat a correlation exists between the percentage of tyrosinamide and the rate of pinocytic uptake of modified polymers. 

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