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Glycyl amino acids

The AAA thus has two photometers in series. Since for every eluting amino acid both signals are recorded, the so-called 570/440 absorbance ratio may be of help in the identification process. As an example the simple primary amino acids have a 570/440 ratio of approximately 6, whereas the sulfur amino acids (cystine, sulfocysteine) have much lower ratios, approaching a value of 1. Small peptides and glycyl-amino acids will react with ninhydrin, an important fact for the diagnosis of prolidase deficiency and aspartylglycosaminuria. [Pg.65]

Cobalt(ll) forms many complexes which can exhibit oxygen-carrying properties (2,19). Reversible oxygen uptake in solutions of cobalt (ll)-histidine (33-36), and cobalt (II) in the presence of a-amino acids and peptides (37—39) has been known for some time. The reaction of cobalt (II) with dipeptide was first observed in enzymic studies involving glycyl-glycine (40). [Pg.7]

The realization of the widespread occurrence of amino acid radicals in enzyme catalysis is recent and has been documented in several reviews (52-61). Among the catalytically essential redox-active amino acids glycyl [e.g., anaerobic class III ribonucleotide reductase (62) and pyruvate formate lyase (63-65)], tryptophanyl [e.g., cytochrome peroxidase (66-68)], cysteinyl [class I and II ribonucleotide reductase (60)], tyrosyl [e.g., class I ribonucleotide reductase (69-71), photosystem II (72, 73), prostaglandin H synthase (74-78)], and modified tyrosyl [e.g., cytochrome c oxidase (79, 80), galactose oxidase (81), glyoxal oxidase (82)] are the most prevalent. The redox potentials of these protein residues are well within the realm of those achievable by biological oxidants. These redox enzymes have emerged as a distinct class of proteins of considerable interest and research activity. [Pg.158]

Racemization is not encountered when 4-unsubstituted-5(477)-oxazolones or 4,4-disubstituted-5(477)-oxazolones are used as reagents. Indeed, 4-unsubstituted-5(47/)-oxazolones function as glycine synthons in the synthesis of A-acylglycyl-a-amino acids. For example, aminolysis of 2-(trifluoromethyl)-5(47/)-oxazolone with a-methylphenylalanine affords A-(trifluoroacetyl)glycyl-a-methylphenylalanine. 4,4-Disubstituted-5(4//)-oxazolones, readily available by alkylation of the monosubstituted derivatives, are very useful intermediates in the synthesis of peptides that incorporate ot,ot-disubstituted amino acids. As an example, 4-(aryl-methyl)-2-phenyl-4-(trifluoromethyl)-5(4//)-oxazolones 260 are key intermediates... [Pg.186]

RIS theory, in the form appropriate for branched molecules, is used to calculate the mean-square unperturbed radius of gyration, < s2>0, for cross-linked polyglycine, poly(L-alanine),poly(L-proline),poly(i-alanyl-D-alanine),poly(i.-prolyl-L-pro lylglycine),poly(L-prolyl-i.-alanylglycine ,poly(glycyl-L-alanyl-L-pro line), andpoly(L-aianyl-L-alanylgIycine).Thecentral amino acid residue in each polypeptide chain is replaced by the L-cysteinyl residue involved in cross-link formation. Each cross-linked molecule is considered to contain two trifunctional branch points, the a-carbon atoms of the two... [Pg.440]

Benzylsuccinate synthase has an amino acid sequence homologous to that of pyruvate formate lyase (p. 799 -801), contains a glycyl radical, and is activated in a manner similar to activation of pyruvate formate lyase. Propose a mechanism for formation of benzylsuccinate. See Krieger et al.383... [Pg.1471]

Chiral a-amino acids The lithium anion of the N-protected glycine amides 3, prepared by reaction of the pyrrolidine with [bis(methylthio)methylene]glycyl pivalic anhydride (DMAP), is alkylated with high diastereoselectivity. The (S)-amino acid (5) is obtained on acid hydrolysis. [Pg.38]

Several different types of chiral additives have been used including (IR)-(-)-ammonium-IO-camphorsulfonic acid, cyclodextrins. proteins, and various amino acid derivatives such as //-benzoxycarbonyl-glycyl-L-proline as well as macrocyclic antibiotics. [Pg.360]

Formally, however, the amino acids contained either in peptides or proteins are named in a fashion related to that used for alkanes. The -ine suffix is replaced by -yl to give, for GAG, glycyl-alanyl-glycine. Peptide and protein sequences are always written and named from the N-terminus to the C-terminus. The C-terminal amino acid retains its full name. [Pg.47]

Synthesis of peptides from amino acids in the solid state or in aqueous solution has been reported with the aid of ATP, Mg2 and free imidazole 34 36). a 4.5 % yield of glycine peptides has been reported in the solid state, 0.6 % yield in aqueous solution 36). Gly-N-pA is formed in a yield of 72.5 % from glycine and chemically synthesized ImpA in aqueous solution, pH 8.0, at room temperature 37). At initial of pH 6.0 glycyl 5 -adenylate (gly-O-pA) and 2 (3 )-0-glycyl adenosine 5 -phosphate (pA-g W are formed 37). [Pg.69]


See other pages where Glycyl amino acids is mentioned: [Pg.16]    [Pg.16]    [Pg.61]    [Pg.253]    [Pg.161]    [Pg.41]    [Pg.201]    [Pg.173]    [Pg.728]    [Pg.387]    [Pg.323]    [Pg.43]    [Pg.100]    [Pg.110]    [Pg.111]    [Pg.186]    [Pg.52]    [Pg.372]    [Pg.80]    [Pg.64]    [Pg.171]    [Pg.29]    [Pg.499]    [Pg.568]    [Pg.614]    [Pg.119]    [Pg.91]    [Pg.609]    [Pg.253]    [Pg.69]    [Pg.56]    [Pg.766]    [Pg.61]    [Pg.468]    [Pg.126]    [Pg.126]    [Pg.447]    [Pg.165]    [Pg.327]    [Pg.320]   


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