Tyrosine ethyl ester

Chemical Name 0-(4-Hydroxy-3,5-dllodophenyl)-3,5-dliodo-0 -methyl tyrosine ethyl ester Common Name —... 

The protease a-chymotrypsin has been used for transesterification reactions by two groups (Entries 7 and 8) [35, 36]. N-Acetyl-l-phenylalanine ethyl ester and N-acetyl-l-tyrosine ethyl ester were transformed into the corresponding propyl esters (Scheme 8.3-2). 

Iborra and co-workers (Entry 8) examined the transesterification of N-acetyl-i-tyrosine ethyl ester in different ionic liquids and compared their stabilizing effect relative to that found with 1-propanol as solvent [36]. Despite the fact that the enzyme activity in the ionic liquids tested reached only 10 to 50 % of the value in 1-propanol, the increased stability resulted in higher final product concentrations. Fixed water contents were used in both studies. 

CN 0-(4-hydroxy-3,5-diiodophcnyl) 3,5-diiodo-a-methyl-DL-tyrosine ethyl ester hydrochloride... 

RN 2544-09-4 MF C,2H,7N04 MW 239.27 EINECS 219-821-2 CN 3-hydroxy-a-methyl-L-tyrosine ethyl ester... 

A polynucleoside with an unnatural polymeric backbone was synthesized by SBP-catalyzed oxidative polymerization of thymidine 5 -p-hydroxyphenylacetate. Chemoenzymafic synthesis of a new class of poly(amino acid), poly(tyrosine) containing no peptide bonds, was achieved by the peroxidase-catalyzed oxidative polymerization of tyrosine ethyl esters, followed by alkaline hydrolysis. Amphiphile higher alkyl ester derivatives were also polymerized in... 

The parameters are usually obtained from a series of initial rate experiments performed at various substrate concentrations. Data for the hydrolysis of benzoyl-L-tyrosine ethyl ester (BTEE) by trypsin at 30 V and pH 7.5 are given below ... 

Abbreviations ADA, adenosine deaminse BAEE, N,a-benzoyl-L-arginine ethyl ester, BTEE, N,oc-benzoyl-L-tyrosine ethyl ester BTNA, N,a-benzoyl-L-tyrosine-p-nitroanilide ZAPA, N,a-benzoylcarbonyl-L-arginine-p-nitroanilide. 

General protease, a-amylase, and exoglucanase activities were estimated using hide powder-, amylose-, and celliilose-azure substrates, respectively, as described earlier (49). Here, standard curves were developed for the hydrolysis of each azure-linked substrate by standard enzymes of known activity. By this method, one cellulose-azure hydrolysis unit corresponds to one filter paper unit, one unit of hide powder-azure activity corresponds to the hydrolysis of 1.0 nmole of iV-benzoyl-L-tyrosine ethyl ester (BTEE) per min, and one amylose-azure unit of activity corresponds to the hydrolysis of 1.0 nmole of maltose from starch per 30 min. 

Flash photolysis has been used to investigate the kinetics of electron transfer from tyrosine to Ru in [Ru(bpy)2(4-Me-4 -CONH-L-tyrosine ethyl ester-2,2 -bpy)] " as a function of pH and temperature. " Model systems for PSII have moved to di- and trimanganese systems containing... 

Particularly noteworthy are the tyrosine-derived polycarbonates (27), a family of polymers based on alkyl esters of desaminotyrosyl-tyrosine. The lead polymer in this family is poly[desaminotyrosyl-tyrosine ethyl ester (DTE) carbonate], a polymer derived from desaminotyrosyl-tyrosine ethyl ester. Other polymers in this series of tyrosine-derived polycarbonates are poly[desaminotyrosyl-tyrosine butyl ester (DTB) carbonate], poly[desaminotyrosyl-tyrosine hexyl ester (DTH) carbonate], and poly [desaminotyrosyl-tyrosine octyl ester (DTO) carbonate], where the letters B, H, and O indicate the presence of butyl, hexyl, or octyl ester pendent chains, respectively. 

Chromophoric acyl group,4,5 The spectrum of the furylacryloyl group depends on the polarity of the surrounding medium, and also on the nature of the moiety to which it is attached. The spectrum of furylacryloyl-L-tyrosine ethyl ester changes slightly when it is bound to chymotrypsin. There are also further changes on formation of the acylenzyme and on the subsequent hydrolysis. The rate constants for acylation and deacylation and the dissociation constant of the Michaelis complex may be measured by the appropriate experiments. 

The Schiff base obtained by (5)-(—)-tyrosine ethyl ester hydrochloride with 2-hydroxybenzaldehyde has been reported to be transformed, via Staudinger... 

Fig. 8. Results of the l3C VACSY experiment on tyrosine ethyl ester.17 The experiment separates 13C (or other) chemical shift anisotropy powder patterns according to isotropic chemical shift. Motional details of each 3C site may then be determined by simulation of the relevant chemical shift anisotropy powder pattern, (a) The complete two-dimensional l3C VACSY spectrum, (b) Slices from the l3C VACSY experiment for the tyrosine phenyl ring at different temperatures. The simulations assume the phenyl ring is undergoing 180° flips at the rates indicated. All spectra are taken from reference 17.

N-Acetyl-L-tyrosine ethyl ester 7 xlO"4 1.43xl03 193 2.7x10s... 

In the first step, we showed by analytical studies that compound 28 was a donor substrate for transketolase in the presence of D-ribose-5-phosphate as acceptor substrate and that in the second step, the hydroxylated aldehyde released 29 led to the P-elimination of protected L-tyrosine. We showed that the free L-tyrosine can thus be obtained by enzymatic deprotection of N-acetyl-L-tyrosine ethyl ester using acylase and subtilisine. In this conditions, it should be possible to carry out this assay in vivo in the presence of host cells overexpressing transketolase and auxotrophic for L-tyrosin. This strategy should offer the first stereospecific selection test of transketolase mutants. The principle of this assay may be extended to other enzymes that can release aldehydes P-substituted by L-tyrosine. 

Fig. 3. Titration data of L-tyrosine ethyl ester HCl in 0.2 M KCl-ethylene glycol according to Eq. (11) of text. Line drawn through the data has slope of 0.0591 v. (Sage and Singer, 1962.)...

Ultraviolet Spectral Properties of Tyrosine Ethyl Ester and Ribonuclease ... 

We may also mention that peptide-bond absorption at somewhat longer wavelengths has been employed by Mitz and Schleuter (1957), and by Schmitt and Seibert (1961) to estimate the rates of digestion by peptidases acting on simple peptides. Schwert and Takenaka (1955) describe difference-spectral methods for assaying chymotrypsin and trypsin with acetyl-L-tyrosine ethyl ester and benzoyl-L-arginine ethyl ester as the respective substrates. 

Figure 15. Conversion of procarboxypeptidase A to carboxypeptidase A by trypsin (151). The subunits are not cyclic polypeptides. ATEEase and HPLAase represents activities of activated subunits I and II on acetyl-1-tyrosine ethyl ester and hippuryl phenyllactic acid, respectively.

Bovine carboxypeptidase A is produced in the pancreas as a zymogen, procarboxypeptidase A, MW = 87,000. The proenzyme is composed of three polypeptide chains (151, schematically shown in Figure 15). On limited digestion with trypsin one or more peptide bonds in subunit II is split resulting in its conversion to an enzyme (ATEEase) having activity on acetyl-L-tyrosine ethyl ester similar to that of chymotrypsin. Continued... 

The following abbreviations are used in the text DEAE-cellulose, diethylamino-ethyl-cellulose CM-cellulose, carboxymethyl-cellulose DFP, diisopropylphospho-fluoridate ATEE, acetyl-n-tyrosine ethyl ester BAEE, benzoyl-L-arginine ethyl ester Tris, tris(hydroxymethyl)aminomethane. 

ATEE, acetyl-L-tyrosine ethyl ester ATryEE, acetyl-L-tryptophan ethyl ester. The numbers below each ester represent methanol concentrations by volumes. 

Reaction of NPA. Chymotrypsin samples oxidized with NBS to different degrees of inactivation were treated with NPA or C -labeled NPA at pH 5.0 or at pH 6.0. The acetylation of the enzyme by NPA is retarded by the NBS oxidation of the protein. The rates of acetylation of various oxidized chymotrypsin samples at pH 5.0 paralleled their relative activities toward V-acetyl-L-tyrosine-Ethyl ester (ATE). However, the net release of p-nitrophenol, measured after the rate of its liberation had approached that of spontaneous hydrolysis, corresponded to a considerable acetylation... 

The partial iodination of tyrosine in wool by propanolic iodine and its lack of reaction in butanol are explained by the observation that iV-acetyl-tyrosine ethyl ester is more extensively iodinated in ethanol than in propanol (Crewther and Dowling, unpublished observations, 1962). Solutions of I2 in n-butanol do not react with the tyrosine derivative. The results of iodination in different solvents are therefore attributable to differences in chemical equilibria. 

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