N-Acetyl alanine

IK Roterman, MH Lambert, KD Gibson, HA Scheraga. A comparison of the CHARMM, AMBER and ECEPP potentials for peptides. II. PHI-PSI maps for N-acetyl alanine N -methyl amide Comparisons, contrasts and simple experimental tests. J Biomol Stiaict Dyn 7 421-453, 198. 

A variety of radical products is observed following gamma radiolysis of the N-acetyl amino acids at 77 K (6), depending on the nature of the side chain of the parent amino acid. In the case of N-acetyl alanine, for example, the intermediates are (i) the anion radical IV (ii) the decarboxylation radical V (iii) the deamination radical VI and (iv) the alpha carbon radical VII. 

The conformational angles derived in this study are unusual values in the Ramachandran map because these maps are based on conformational energy calculations for molecules as N-acetyl-alanine-N -methyl amide, which do not incorporate charged groups and thus will reproduce an uncharged peptide fragment better than an aqueous solution of a zwitterionic peptide. 

I. K. Roterman, M. H. Lambert, K. D. Gibson, and H. A. Scheraga,. Biomol, Struct. Dyn., 7, 421 (1989). A Comparison of the CHARMM, AMBER and ECEPP Potentials for Peptides. II. —d Maps for N-Acetyl Alanine N -Methyl Amide Comparisons, Contrasts and Simple Experimental Tests. 

In the asymmetric hydrogenation of acetamidoacrylate in water with this cationic (HO)4-BASPHOS catalyst (S)-N-acetyl alanine was obtained in quantitative yield and in more than 99% ee. Noteworthy is the unusually short time necessary in or-... 

L-specific carbamoylase from Pseudomonas putida IFO 12996 also hydrolyzes P-ureidopropionate 14, 36. The enzyme from Pseudomonas putida IFO 12996 was shown to be strictly L-selective and to be active on L-N-formyl- and also on L-N-acetyl-alanine 36. In this context it may be of interest that Runser and Meyer described a d-hydantoinase with no dihydropyrimidinase activity 37 and Ogawa et al. reported on the occurrence of a D-N-carbamoylase with no relation to a D-hydantoinase 38. ... 

Hydroxyoxazolidin-2-ones 55 result from the action of aryl isocyanates on the hydroxy ketones 54 (94JPR509). N-acetyl-alanine, valine or leucine and dimethylformamido/ phosphorus oxychloride yield the (formyl-methylene )oxazolidinones 56 (R = Me, i-Pr or... 

Lucas, B. Gregoire, G. Lemaire, J. Maitre, R Glotin, F. Scheimann, J.R Desfrancois, C. Infrared multiphoton dissociation spectroscopy of protonated N-acetyl-alanine and alanyl-histidine. Int. J. Mass Spectrom. 2005, 243, 105-113. 

Highly functionalized halides give generally positive results. p-Iodo N-acetyl-alanine methyl ester was used to introduce the amino acid residue into an olefinic protected sugar (Fig. 57),300... 

The first example of a combination of a metal-catalyzed substrate synthesis with a biotransformation conducted in a one-pot maimer proceeding according to Scheme 19.23 was reported by Hanefeld, Maschmeyer, Sheldon, and coworkers in 2006 [58]. In this pioneering work, enantioselective hydrogenation of methyl N-acetyl amino acrylate (72) with a heterogenized rhodium-diphosphane complex as catalyst gave the N-acetyl alanine (S)-73 with 100% conversion and 95% ee. This intermediate was then directly converted in situ after separation of the immobilized metal catalyst by means of an L-amino acylase (Scheme 19.23). This enzymatic resolution then led to the formation of the desired amino acid L-alanine (l-74 (S)-74) with 98% conversion and with an excellent enantiomeric excess of >98%. 

Both enantiomers of N-acetyl alanine have a free carboxy group that can react with an amine in an acid-base reaction. If a chiral amine is used, such as (R)-oc-methylbenzylamine, the two salts formed are diastereomers, not enantiomers. Diastereomers can be physically separated from each other, so the compound that converts enantiomers into diastereomers is called a resolving agent. Either enantiomer of the resolving agent can be nsed. 

The base peak at m/e 202 (M-107) corresponded to the N-acetyl-alanine TMS ester moiety. 

Diethyl ether, methyl n-propyl ether, diethylamine, N-methyl-1 -propanamine, acetone, allyl alcohol, dimethylformamide, propanamide, 2-methylpropan-amide, 2,2-dimethylpropanamide, benzamide, dichloromethane, toluene, ethyl N-acetyl-glycinate, -alaninate, -methioninate, and -aspartate, ethyl acetate, tetrahydrofuran... 

Selectivity studies with DTU indicated marked discrimination in the clathrate formation 23,45). As in other types of clathrates, the steric factor is important in differentiation between compounds of similar functionality but different shape. For example, DTU forms crystalline complexes with some alcohols (methanol, ethanol, propanol, 1-butanol) but not with others (2-butanol). It complexes the ethyl esters of N-acetyl derivatives of glycine, alanine, methionine and aspartic acid, but not of proline, serine, phenylalanine and glutamic acid. 

B. Theoretical Studies of Aqueous N-Acetyl-L-alanine N -Methylamide... 

Schafer, L., I. S. Bin Drees, R. F. Frey, C. Van Alsenoy, and J. D. Ewbank. 1995c. Molecular Orbital Constrained Gas Electron Diffraction Study of N-Acetyl N -MEthyl Alanine Amide. J. Mol. Struct. (Theochem) 338, 71-82. 

Many of the conformational properties of peptide systems, including protein conformation, can be approximated in terms of the local interactions encountered in dipeptides, where the two torsional angles 4> (N-C(a)) and < i (C(a)-C ) are the main conformational variables. N-acetyl N -methyl alanine amide, shown in Fig. 7.11, is a model dipeptide that has been the subject of numerous computational studies. 

Fig. 7.11 N-acetyl N -methyl alanine amide. Identification of the 4> (N-C(a)) and i / (C(a)-C ) torsional angles.

Cycloserine (Fig- 4) is produced by several species of Streptomyces. One of the basic glycosyl components of the bacterial cell wall, n-acetyl-muramic acid (the product of Mur A and MurB), is modified by the addition of the first three amino acids sequentially by MurC, MurD and MurE enzymes. A dipeptide, D-alanyl-D-alanine is then added to make the pentapeptide. In bacteria, L-alanine is the native form and it is converted to D-alanine form by alanine racemase (Air). Two D-alanines are joined by D-ala-D-ala ligase (DdlA) to synthesize the dipeptide. Cycloserine resembles the substrate for Air and Ddl and inhibits their respective reactions in stage I of the peptidoglycan biosynthesis (Fig. 2). 

C]-DL-Phenylalanin5 [3- 11C]-L-Phenylalanina [.3-l C]-D-(2-Naphthyl)-alanin-Hydrochlorid4 N-Acetyl-2,3-ditntio-o- ( 2-naphthyl) -alanin9... 

---