Phenylalanine chemical structure

B 10. In your biochemistry research project, you have isolated a new protein from spinach leaves. You wish to do a Western blot experiment with the protein to help determine its chemical structure and/or biological function. An amino acid analysis of the protein showed a great abundance of phenylalanine, leucine, and valine. What would be your choice of membrane for the blotting experiments ... 

Twenty amino acids are commonly found in proteins, (a) Draw the chemical structures of alanine, glycine, phenylalanine, and cysteine (see Table 19.4). 

Otagiri et al. (22) used model peptides composed of arginine, proline, and phenylalanine to ascertain the relationship between bitter flavor and chemical structure. They reported that the presence of the hydrophobic amino acid at the C terminus and the basic amino acid at the N terminus brought about an increase in the bitterness of di- and tripeptides. They further noted a strong bitter taste when arginine was located next to proline and a synergistic effect in the peptides (Arg)r(Pro) ,-(Phe) (/ = 1,2 m, n = 1, 3) as the number of amino acids increased. Birch and Kemp (23) related the apparent specific volume of amino acids to taste. 

Scheme 2 Chemical structure of polypeptides containing p-phenylazo-L-phenylalanine and y-benzyl-L-glutamate residues (II).

Af-Fmoc L-F2Pmp(OEt)2-OH (5) is indexed within the ACS system under registry number 160751-44-0 bearing the chemical name, 4-(difluoro-di-ethyl-phosphono-methyl)-Af-[(9H-9-ylmethoxy)carbonyl]-L-phenylalanine. The associated chemical structure is currently incorrectiy given as the free phosphonic acid, A-Fmoc l-F2Pmp-OH (6). 

Phenylalanine catabolism, 468 chemical structure, 19 plasma conoentralion, 46o sparing by tyrosine, 467,469 Phenylketonuria, 467,469 Phenylpyruvic acid, 469 FhIP,889,B90 Phlebotomy, 759 Phlorizin hydrolase, 109-110 Phorbol esters, cancer and, 916 Phosphatases, 54, 66 Phosphate, 694 in biologLcal fluids, 696 in bore, 697... 

Although phenylalanine and tyrosine are closely related in chemical structure and in mammalian metabolism, these amino acids form separate sections of the Amaryllidaceae alkaloids. Phenylalanine contains no oxygen in the aromatic ring yet it serves as a primary precursor of the C-6—C-1 fragment in alkaloids which may contain as many as three oxygenated substituents in ring A. Tjrosine is a universal precursor of ring C and the two-carbon side chain (Ce—C2). Phenylalanine is not... 

Ditryptophenaline (56), mp 204-205°C, was isolated from the mycelium of Asp. flavus during the investigation for food-borne mycotoxin by Biichi and coworkers (104). The chemical formula, C42H4QNg04, is assigned on the basis of the high-resolution mass spectrum (m/z 692.3095), and the NMR spectrum indicates a dimeric structure. It possesses a diketopiperazine ring derived from tryptophan and phenylalanine and has UV absorptions at 244 and 303 nm. The chemical structure was determined by single-crystal X-ray experiments. Later, Hino and co-... 

FIGURE 8.16 Chemical structure of random PEAs having hydrophobic L-phenylalanine imits and different percentages of hydrophiUc L-lysine units. After deprotection, PEAs are provided of functional amine pendant groups. 

FIGURE 8.19 Chemical structure of triblock poly(ether ester amide)s constituted by poly(e-caprolactone), L-phenylalanine (Phe), and unsaturated and saturated aliphatic acid units. 

As described previously, the origins of the three types of curare are the extracts of Chondodendron (Menispermaceae) and/or Strychnos (Loganiaceae) plants. Among them, the toxic components of Strychnos plants are C-curarine and C-toxiferine I, etc.These constituents are alkaloids derived from tryptophan and are described in the next (Section 2.15).The C- is the initial of calabash. On the other hand, the toxic principle of tubocu-rare is d-tubocurarine, an alkaloid derived from phenylalanine. The alkaloid was first isolated as a hydrochloride from tubocurare and is preserved in the Museum of the British Society of Pharmacy [1]. The chemical structure of d-tubocurarine was first proposed as a bisbenzylisoquinoline with two quaternary ammonium moieties. This was revised in 1970 to be the structure with one tertiary and one quaternary amine after X-ray crystallographic analysis [2]. 

The chemical structure of ephedrine is similar to that of mescaline, a hallucinogen, and it was thought initially that this alkaloid also originated from phenylalanine, as in the case of mescaline. However, when [3- C] phenylalanine was fed to E. distachya, it was established that this unit was incorporated into the aromatic ring of the C6-C2-N moiety of (-)-ephedrine [10]. 

Most alkaloids have basic properties coimected with a heterocyclic tertiary nitrogen. Notable exceptions are colchicine, caffeine, and paclitaxel. Most alkaloids are biosynthetically derived from amino acids such as phenylalanine, tyrosine, tryptophan, ornithine, and lysine. Alkaloids represent a wide variety of chemical structures. About 20000 alkaloids are known, most being isolated from plants. But alkaloids have also been found in microorganisms, marine organisms such as algae, dinoflagellates, and puffer fish, and terrestrial animals such as insects, salamanders, and toads. 

Fig. 21.5 The chemical structures of the drug carbamazepine and the receptor amino acids phenylalanine and tryptophan...

Fig. 9.4 Chemical structure of a peptide bond. Amino acids (here two phenylalanines) are joined through peptide bonds to form proteins...

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