Amino acid analogs

Much of what is known about the chymotrypsin mechanism is based on studies of the hydrolysis of artificial substrates—simple organic esters, such as /Miitrophenylacetate, and methyl esters of amino acid analogs, such as... 

A CONVENIENT PREPARATION OF AN ORTHOGONALLY PROTECTED C ,C -DISUBSTITUTED AMINO ACID ANALOG OF LYSINE l-tert-BUTYLOXYCARBONYL-4-((9-FLUORENYLMETHYLOXYCARBONYL)AMINO)-PIPERIDINE-4-... 

Drugs (nonsteroidal anti-inflammatory, antineopiastic agents, aicohoi) Denatured proteins (amino acid analogs)... 

Both enantiomers of the auxiliary are available, so either enantiomeric product can be obtained. This methodology has been applied to a number of enantioselective syntheses.95 For example, the glycine derivative 14 can be used to prepare a-amino acid analogs.96... 

Various salts can achieve chelation but ZnCl2 and MgCl2 are suitable for most cases. The rearrangement is a useful reaction for preparing amino acid analogs and has also been applied to synthesis of modified dipeptides.250... 

This version of the Curtius rearrangement has been applied to the synthesis of amino acid analogs and structures containing amino acids. Several m-2-aminocyclopropane carboxylate esters were prepared by selective hydrolysis of cyclopropane-1,2-dicarboxylates, followed by reaction with DPPA.267... 

Synthesis of Amino Acid Analogs. J. Amer. chem. Soc. 77, 1 (1955). 

Figure 17.11 Amino acid analogs containing either azido or alkyne modifications can be fed to cells and these monomers incorporated into expressed proteins.

Unusual amino acids include a class of unnatural a-amino acids such as phenylalanine, tyrosine, alanine, tryptophan, and glycine analogs, and f)-amino acid analogs containing 1,2,3,4-tetrahydroisoquinoline, tetraline, l,2,3,4-tetrahydro-2-carboline, cyclopentane, cyclohexane, cyclohexene, bicyclo[2.2.1]heptane or heptene skeletons. Different selectors were exploited for the separation of unusual amino acids, most of the production being made by Peter and coworkers teicoplanin [41, 56, 84, 90, 93, 124, 141-144], ristocetin A [33, 94, 145, 146], and TAG [56, 147]. Enantiomeric and diastereomeric separations of cyclic -substituted a-amino acids were reported by other authors on a teicoplanin CSP [88, 89], Ester and amide derivatives of tryptophan and phenylalanine were recently analyzed on a Me-TAG CSP [58],... 

The pyridoxal amino acid analog (Pal) was stereoselectively synthesized from a readily available pyridoxol derivative and the residue was incorporated into peptides at the alcohol oxidation state in protected form. Oxidation of the 4 -alcohol group to the desired aldehyde was achieved post-synthetically on free. 

Remarkably, incorporation of fluorinated amino acids into proteins can also be accomplished in vivo. This supposes that the fluorinated amino acid analogs are recognized by the appropriate amino acyl-tRNA synthetase enzyme with efficiency similar to that of the natural amino acid. The proliferase response elicited by a fluorinated analog (a trifluoroisoleucine derivative) of murine interleukin-2 produced in an appropriate Escherichia coli strain was nearly as high as that of the authentic cytokine, indicating folding into an authentic, native structure [84],... 

Speck, P., F. Escher, and J. Solms. Effect of salt pretreatment on quality and storage stability of air-dried carrots. Lebensm Wiss Technol 1977 10 308. Widholm, J. Selection and characterization of a Daucus carota cell line resistant to four amino acid analogs. J Exp Bot 1978 29 1111. 

Goldberg AL (1972) Degradation of abnormal proteins in Escherichia coli (protein breakdown-protein structure-mistranslation-amino acid analogs-puromycin). Proc Natl Acad Sci USA 69 422 26... 

A notable finding was the defective transport of D-glucose, uridine, and two amino acid analogs (2-aminobutanoate and cycloleucine) in chick-embryo cells in which glycosylation of proteins was prevented by tunicamycin. Other membrane-associated processes, such as the enzymic activities of Na/K ATPase and adenylate cyclase, or the stimulation of adenylate cyclase by a prostaglandin and cholerae toxin, were not affected.546... 

In addition to the 20 amino acids most frequently found in proteins a large group of amino acids occur in plants, bacteria, and animals that are not found in proteins. Some are found in peptide linkages in compounds that are important as cell wall or capsular structures in bacteria or as antibiotic substances produced by bacteria and fungi. Others are found as free amino acids in seeds and other plant structures. Some amino acids are never found in proteins. These nonprotein amino acids, numbering in the hundreds, include precursors of normal amino acids, such as homoserine and diaminopimelate intermediates in catabolic pathways, such as pipecolic acid d enantiomers of normal amino acids and amino acid analogs, such as azetidine-2-carboxylic acid and canavanine, that might be formed by unique pathways or by modification of normal amino acid biosynthetic pathways. 

Fowden, L., P. J. Lea, and E. A. Bell, The nonprotein amino acids of plants. Adv. Enzymol. 50 117,1979. A discussion of the occurrence and biosynthesis of naturally occurring amino acid analogs in plants. 

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