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Amino acid acylations

Brusilow, S., Tinker, J. and Batshaw, M. L. Amino acid acylation A mechanism of nitrogen excretion in inborn errors of urea synthesis. Science 207 659,1980. [Pg.683]

Morpholine-2,5-diones have been prepared by intramolecular, nucleophilic cleavage of polystyrene-bound amino acids acylated with a-hydroxy acids (Entry 2, Table... [Pg.452]

The terminal amino and carboxyl groups react in the same way as the corresponding amino acids (acylation, animation, esterification, etc.). Some of the reactions of the amino groups (with ninhydrin, orthophthaldehyde, fluorescamine, etc.) are used for detection purposes, as will be discussed later. Peptides also react in ways that free amino acids do not, like the classic biuret reaction, which consists of the formation of a colored complex with a transition metal (Cu, Ni, etc.)... [Pg.100]

Restricted rotation, as surface conjestion increases, was postulated as being responsible for the observed optical rotations as the generations increase,1251 the possibility of racemization during amino acid acylation was also investigated. Amino acid isolation and high-performance liquid chromatography (HPLC) analysis following acidic hydrolysis of the asymmetric dendrimers revealed an enantiomeric excess > 96 %. [Pg.188]

The most important mechanism of racemization involves the formation of oxazol-5(4//)-ones.f In this mechanism it was shown that the properties of the amino protecting group might be associated with the tendency for racemization. The activation of the carboxy moiety of A -acyl amino acids (acyl = Ac, Bz, peptidyl, etc.) readily results in the formation of oxazol-5(4//)-ones, which give rise to chirally unstable intermediates via tautomerization of the oxazol-5(4//)-one (Scheme 4). [Pg.593]

In most cases, it is best to employ a temperature near or below the catalyst s thermostable limit (determined from the technical hterature, the manufacturer, or through screening experiments). However, in a few cases, low temperature operahon is desired. One example is acyl transfer reachons involving pephde. A common problem associated with this category is the occurrence of a side reachon, hydrolysis. Moreover, a compehhon exists between the amino acid acyl acceptor and water, both acting as nucleophiles toward the acyl-enzyme intermediate. Adlercreutz and co-workers discovered that the selectivity of chymotrypsin toward acyl exchange over hydrolysis increased as temperature decreased. - Hence, operation is best at lower temperatures. A second situation is when low temperature selectively precipitates the desired product (discussed below). [Pg.203]

Different sub-classes of peptaibols are recognized the long sequence peptaibols (18-20 residues), short sequence peptaibols (11-16 residues) and liptopeptaibols which contain 7 or 11 residues with the N-terminal amino acid acylated by a short lipidic chain instead of an acetyl group. [Pg.225]

N-Alkyl amino acids, acyl amino acids and protein-derived amphoterics... [Pg.51]

Ohba and co-workers developed a general synthesis of chiral iV-protected 5-(aminomethyl)oxazoles from a-lithiated isocyanides and Af-protected amino acid esters (Scheme 1.101). Metalation of an alkyl or benzyl isocyanide with n-BuLi or LDA and acylation with an A-Boc-ot-amino acid methyl ester afforded an iV-Boc-a-amino acid acyl isocyanide 369, which cyclized to a chiral A-Boc-5-(aminomethyl) oxazole 370. The products were obtained in > 98% ee based on chiral HPLC analysis. The yields of 370 were somewhat variable, ranging from 45 to 91%. A-Boc-protected glycine, alanine, phenylalanine, proline, serine, and (9-benzyl serine were all compatible with these reaction conditions. [Pg.80]

When the transfer of activated valine from enzyme to tRNA is measured at various temperatures, the transfer is quantitative up to 55° C, but then it drops slowly between 55 and 60° C (80% of transfer at 60° C) and rapidly between 60 and 65° C (no transfer at 65° C). Yet at 65° C the enzyme catalyzes the amino acid acylation at normal rates. Again the findings were interpreted to mean that conformational changes in tRNA interfered with its ability to react with the enzyme. Transfer RNA forms a link between most of the individual components involved in protein synthesis, amino acyl RNA, ribosomes, and messenger RNA. [Pg.113]

Yao K, Zhao M, Zhang X, Wang Y, Li L, Zheng M, Peng S (2011) A class of oral N-[(lS,3S)-l-methyl-l,2,3,4-tetrahydro-b-carboline-3-carbonyl]- NO-(amino-acid-acyl) hydrazine Discovery, synthesis, in vitro anti-platelet aggregation/in vivo anti-thrombotic evaluation and 3D QSAR analysis. Eur J Med Chem 46 3237-3249... [Pg.572]

Many of the reactions of carboxylic acids and amines appear in the chemistry of amino acids. Acylation and Fischer esterification are two examples.There are some new reactions, however, that involve both the amino and the acid groups. Reaction with ninhydrin is an example. [Pg.1189]

Few microbial proteases acting on n-peptides are known. The alkaline D-peptidase (ADP) from Bacillus cereus is related to Du-carboxypeptidase and p-lactamases. These enz unes have an accessible groove in which the nucleophilic serine and other catalytic amino acids are located. This n-peptidase could be applied for the synthesis of the 92-amino acid peptidyl prolyl cis-trans isomerase from Escherichia coli by condensation of two peptide fragments, of which the 35-amino acid acyl donor was activated as the OGp ester [62]. Thus the D-amino acid-selective enzyme was used for preparing a protein composed of L-amino acids and making the product insensitive to hydrolysis by the coupling enzyme. [Pg.405]


See other pages where Amino acid acylations is mentioned: [Pg.588]    [Pg.63]    [Pg.266]    [Pg.163]    [Pg.1170]    [Pg.1172]    [Pg.63]    [Pg.103]    [Pg.23]    [Pg.359]    [Pg.230]    [Pg.1170]    [Pg.117]    [Pg.39]    [Pg.147]    [Pg.1068]   
See also in sourсe #XX -- [ Pg.812 ]




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4- Acyl-5-amino

A-Acylated amino acid derivatives

A-Amino acids, acylation

Acyl amino acid-releasing enzyme

Acyl amino acids, alkylations, sodium hydride

Acyl azides amino acids

Acyl bromide, amino acid synthesis with

Acylated amino acids

Acylated amino acids

Acylated amino acids acyl chain length

Acylated amino acids characterization

Acylated amino acids description

Acylated amino acids hydrolysis

Acylated amino acids specifications

Acylated amino acids titration

Acylation amino groups with acidic chains

Acylation of amino acids

Acylation reactions amino acid conjugation

Amino acid derivatives acyl-CoAs

Amino acid derivatives, acyl

Amino acid derivatives, acyl migration

Amino acid, acylation fruit

Amino acids N-acylation

Amino acids acylating agents

Amino acids acylation reactions

Amino acids from acyl halides

Amino acids, acylation syntheses

Amino acids, preparation acyl derivatives

Amino acylations

Coenzyme amino acid acylation

N-acyl amino acids

Substrate Specificity of Ketosynthase Domains Part II Amino Acid-Containing Acyl Chains

TV-Acyl Amino Acid

V-acyl amino acids

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