Amino acid amides and

This zinc-dependent enzyme [EC 3.4.11.1], also referred to as cytosol aminopeptidase, leucyl aminopeptidase, and peptidase S, catalyzes the hydrolysis of a terminal peptide bond such that there is a release of an N-terminal amino acid, Xaa-Xbb-, in which Xaa is preferably a leucyl residue, but may be other aminoacyl residues including prolyl (although not arginyl or lysyl). Xbb may be prolyl. In addition, amino acid amides and methyl esters are also readily hydrolyzed, but the rates with arylamides are exceedingly slow. The enzyme is activated by heavy metal ions. 

Leschke C, Storm R, Breitweg-Lehmann E, Exner T, Nurnberg B, Schunack W (1997) Alkyl-substituted amino acid amides and analogous di- and triamines new non-peptide G protein activators. J Med Chem 40 3130-3139... 

One reason for an otherwise apparently excessive interest in Co(trien)X2+ systems is the use of ds-Co(OH)(trien)(OH2)2+ in the hydrolysis of amino acid esters, amino acid amides and peptides785 to form cis-px- and cis-/J2-Co(trien)(aa)2+ (aa = amino acid) complexes.16 In principle, a peptide could be degraded in a stepwise manner and each amino acid residue successively characterized. By the introduction of a chiral center into the backbone of the trien moiety, it was hoped to make such reactions stereoselective. Consequently, while fully A-alkylated trien systems have been widely investigated for M11 central ions, the C-alkylated trien systems have been almost exclusively the reserve of the Co111 chemist (Table 11). 

Table 12.7 Yields of a-chymotrypsin-catalyzed peptide synthesis in water and ice using maleoyl-L-tyrosine methyl ester as acyl donor and various peptides, amino acid amides, and amino acids as nucleophiles (Schuster, 1990).

The mechanism of retention on chiral phases that is based on multiple hydrogen bonding formation involves the formation of base pairs and triple hydrogen bonds between the solutes and the chiral stationary phase 95 Fundamental work in this area has been done by Hara and Dobashi,96 97 using amino acid amide and tartaric acid amide phases. In addition, N,N -2,6-pyridinediyl bis(alkanamides) chemically bonded to silica gel have been described for the resolution of barbiturates 95... 

Stein, R.L. and Strimpler, A.M. 1987. Catalysis by human leukocyte elastase aminolysis of acyl enzymes by amino acid amides and peptides. Biochemistry, 26, 2238-2242. 

Figure 3.13. Chemical composition and structure of saccharides, chlorides, amino sugars, amino acids, amides, and a heterocyclic amino acid.

From a.-Amino Acid Amides and Amidines a-Amino acid amides, which fall into the amine-imine class according to the general model (beginning of Section II,B), are converted to 3-alkyl-4-hydroxy-l,2,5-thiadiazoles by reaction with sulfur mono-chloride, thionyl chloride, or thionyl aniline. A large number of -amino acid amides were employed in the synthesis (see Table I)... 

Co(trien)(NH3)2] + has been isolated, and only the meso trans isomers (197-198) with two different axial ligands, remain to be distinguished. There is also an extensive chemistry of N and C-alkylated derivatives of (178 180) as cA-[Co(OH)(trien)(OH2)] assists the hydrolysis of amino acid esters, amino acid amides, and peptides to form cis-fi (194) and cA-jS2-[Co(OA0(trien)] + (195)(( A = amino acid) complexes. Chiral alkylated trien ligands have the potential for chiral stereospecificity in such reactions. 

Derivatization of Amines. Amino Acids. Amides, and Imides for GC Anal... 

The second group of hydroxy compound derivatization reactions includes acylation of OH groups with the formation of esters. The most important are listed below (for the table of physicochemical and gas chromatographic constants of acylation reagents refer to the entry Derivatization of Amines, Amino Acids, Amides, and Imides for GC Analysis). 

Monomethyl phthalate, BOP, ZnCB, DIPEA, CH3CN, sonication, 16 h, 53-95 % yield. These conditions result in racemization free protection of amino acid amides and esters. PyBOP can also be used as a dehydrating agent. ... 

Table 3.1 displays rate constants for the hydrogen abstraction by cysteamine thiyi radicals from several N-acetyl-amino acid amides and diketopiperazines [84]. 

Table 12.5-8. Clostripain-catalyzed coupling of 4-guanidinophenyl esters of 4-phenylbutyric acid (Pbu-OGp) and benzoyl-fi-alanine (Bz-(S-Ala-OGp), respectively, with various amino acid amides and peptides according to Gunther et al.[,99 .

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