Fl-Alanine

Figure 7.5. Peptide array construction by SPOT-synthesis. fl-alanine groups (b-A) interact with the cellulose filter that serves as a planar support. Peptide synthesis then proceeds using Fmoc chemistries using the fl-alanine group as a starting point. The peptide is attached to the filter via its carboxy-terminus. In this case, lysine is added at the second position and various amino acids are present at the amino terminus of the peptide.

Figure 30. Optical microscope pictures of the 010 faces of a glycine crystal after partial dissolution in the presence of (fl)-alanine (a) (010) face (6) (0T0) face.

Support-bound alkenes substituted with at least one electron-withdrawing group can react with primary or secondary amines (Table 10.6). If acrylates are used as Michael acceptors, the products (fl-alanine derivatives) are generally stable and do not undergo [l-elimination either upon N-acylation or upon treatment with TFA (for a longer synthetic sequence with a support-bound 2-(l-piperazinyl)propionate, see [42]). Suitable solvents for the addition of amines to electron-poor alkenes are THF, NMP, and DMSO. DMF is less suitable because it often contains dimethylamine, which also adds to Michael acceptors [112],... 

Except for glycine, all A. a. contain at least one asymmetric C-atom. With few exceptions, naturally occurring A. a. have the L-configuration. o-A.a. occur in the cell walls, capsules and culture media of some microorganisms, and in many antibiotics. A. a. lacking an a-amino group (()-, y-, b-A.a., e.g. fl-alanine) occur as the free acids or as components of natural products, but not in proteins. 

Analytical conditions are shown in Table 20.4. A urine sample was directly injected into this system. Urinary pantothenic acid is separated in the reversed phase column and hydrolysed to fl-alanine and pantoic acid. The product P-alanine reacts with o-phthaldialdehyde (OPA) and 3-mercaptopropionic acid (3-MPA), and is derivatized to l-alkylthio-2-alkylisoindole which is detected by fluorescence (Takahashi et al. 2009). 

Figure 10.7 Onset of the photopotential under open-circuit conditions in a fl-alanine solution of composition as indicated.

The hydrochlorides of some dipeptides have a salty taste, which suggests the possibility of using them as a replacement for sodium chloride for people who need to cut down their salt intake for health reasons (see Section 8.3.2). L-Omithyl taurine (2-93) and L-lysyl taurine hydrochlorides (2-94) also exhibit a salty taste of similar quality and intensity as sodium chloride. A weaker salty taste is found in the hydrochloride of L-omithyl-fl-alanine (2-95) and the hydrochloride of L-ornithyl-y-aminobutync acid. 

The stability of pantothenic add in aqueous solutions depends greatly on the pH value. The vitamin is most stable in weakly acidic (pH 4 5) solutions, but in acidic and alkaline media the amide Hnkage is hydrolysed and pantothenic add yields pantoic add (or its salt) and fl-alanine. The enzyme pantothenase of some baderia specifically cleaves pantothenic add into the same products. In acidic solutions, pantoic acid spontaneously dehydrates to form lactone, (R)-2-hydroxy-3,3-dimethylbutano-4-lactone, which is called pantoyllactone or pantolactone (5-73). Analogously, products of panthenol hydrolysis are pantoic add... 

AMPHOSOL AT-2 Mona AT-1200 STEPANATEAT-2 surfactant, acid cleaners fl-Alanine, N-(2-cartioxyethylK N-(3-(C12-15-alkyloxy)propyl) derivs., mono-sodlinn salts Amphoteric N Behenyl amlnoethyl Imidazoline Berol 226 Berol 556 Cocoyl amlnoethyl Imidazoline Cola Teric CA-35 Cola Teric MSC Cola Teric MSC-NA Cola Teric ZF-50 ... 

Except for cysteine, only S amino acids occur in proteins. Several R amino acids are also found in nature, however. (ft)-Serine is found in earthworms, and (R)-alanine is found in insect larvae. Draw Fischer projections of (fl)-serine and (J )-alanine. Are these Don amino acids ... 

McLean JH, Darby-King A, Sullivan RM, et al Serotonergic influence on olfactory learning in the neonate rat. Behav Neural Biol 60 152-162, 1993 McNally RJ, Calamari JE Obsessive-compulsive disorder in a mentally retarded woman. Br J Psychiatry 155 116-117, 1989 McNamara RK, Lenox RH Comparative distribution of myristoylated alanine-rich C kinase substrate (MARCKS) and Fl/GAP-43 gene expression in the adult rat brain. J Comp Neurol 379 48-71, 1997... 

Lippmaa and coworkers used 13C NMR titration to measure secondary deuterium IEs on acidities of carboxylic acids.24 The results are listed in Table 2. It is remarkable that the IEs show only a small attenuation with distance, so that the IE from three y-deuteriums in alanine is greater than that from two (3-deuteriums in glycine. As a consequence the IEs can be detected and measured from deuteriums as far as seven bonds away from the carboxyl, as in caproic-6,6,6-fl 3 acid. Moreover, in benzoic acids the IE is practically independent of the site of deuteration. 

Figure 7. Formation of free radical and other intermediates in the reaction of glucose with fi-alanine. The mixture (each 2 M) with aqueous alkali solution (0.1 N NaOH) was heated in a boiling water bath. Key , free radical O, browning A, 1-fl-alanino-l-deoxyfructose and , 3-deoxyglucosone. (Reproduced with...

APRON 2E APRON FL CG 117 CGA 48988 D,L-N-(2,6-DIMETHYLPHENYL)-N-(2 -METHOXYACET-YL)ALANINATE de METHYLE N-(2,6-DIMETHYL-PHENYL)-N-(METHOXYACETYL)-ALANINE METHYL ESTER N-(2,6-DIMETHYLPHENYL)-N-(METHOXY-ACETYL)-DL-AL, NINE METHYL ESTER METALAXIL... 

Margolis FL, Grillo M, Kawano T, Farbman AL 1985. Carnosine synthesis in olfactory tissue during ontogeny Effect of exogenous b-alanine. J Neurochem 44 1459-1464. 

DL-[l- C]Valine, D-, L-, and DL-fl- CJalanine, and lysergylvaline (31 label as shown) have been studied as precursors for ergocornine (32) and ergo-cryptine (33), examined mostly as the 3 1 mixture ergotoxine. L-Alanine and... 

Recently, from the inspection of NMR spectra the presence of nonplanar peptide bonds in solution have been reported. One of them is with poly(N-n thyl-L-alanine) (6S) and its monomeric amide (64) in DCA-containing solvent. The other has been reported by Grathwohl et al. (65) with Cyclo-(Gly4). Grathwohl et fl/. compared the NMR ectra in TFA or DMSO of Cyclo-(Gly4) with those of... 

Figure 2. Signs of upper half of hexadecant above the plane of chelate ring with superimposed chelated tripeptide composed of L-alanine residues. (Modified from Martin et fl/., 1967.)...

Fig. 13.3. Biogenesis of isoprephenic acid and 3(3-carboxyphenyl)alanine (modified from Rosenthal, 1982 used with permission of the copyright owner. Academic Press, Orlando, FL).

L-/-Leucine catalyses model aldols in moderate to high yields, des, and ees, being superior to leucine, valine, alanine, and proline for the reactions examined. " A simple chiral l°-3° diamine (52, derived fl om L-Meucine) and a tungstate (H4SiWj204o) catalyse direct cross-aldols of acetaldehyde, giving 99% yield in 4h, and ee up to 92%. ... 

However, it should be noted that the concept of carbohydrates as chiral synthons has always fascinated sugar chemists as the excellent 1972 review by Inch will attest 42). Thus in order to preserve historical perspective three antecedents for the use of sugars in asymmetric syntheses are noted in Scheme 1. First is Wolfrom s proof of the structure of (-t-)-alanine by synthesis from D-glucosamine 102). Second is the synthesis of the optically pure mandelic acid derivatives from 2,3-4,5-di-O-isopropylidene-fl/tfeAy o-D-arabinose (1) by Bonner (9), and third is Lemieux s synthesis of ethanol-l-d from diacetone glucose (6 a, Scheme 2) via the deuterated xylose (2) (57). 

Chloroform is passed through an alumina column (Woelm) and stored over a Linde 4A molecular sieve for not more than 2 hr before use. Phosphorus pentachloride (135 mg) is added to 2.5 ml of dry chloroform and dissolved by stirring at 26° for 30 min. The solution is then chilled on ice and 105 mg of the serine methyl ester hydrochloride (prepared as described above) is added in small portions over a 30-min period with stirring. The solution is stirred at 26° for 2 hr until it clarifies crystals then begin to form. The mixture is placed at 0° for 18 hr dry petroleum ether (b.p. 70°-90°) is added and the crystals of fl-chloro-L-alanine methylester hydrochloride are collected and washed with dry petroleum ether. The crystals (92 mg) are suspended in 3 ml of 6 M HCl and refluxed for 1 hr. The solution is flash-evaporated, and the residue is dissolved in water and flash-evaporated again. This procedure is repeated once with water and then twice with benzene. 

The inactivation and labeling of L-aspartate-/ -decarboxylase probably involves nucleophilic attack by a group on the enzyme on the fl-carbon atom of the a-aminoacrylate-Schiff base formed in the interaction of 8-chloro-L-alanine and enzyme-bound pyridoxal 5 -phosphate. Labeling of the enzyme thus requires conditions under which the catalytic reaction can occur. An excess of yS-chloro-n-alanine is therefore required, since a substantial portion of the analog is converted to pyruvate before... 

The three enzymes sensitive to penicillins, i.e., peptidoglycan transpeptidase, D-alanine earboxypeptldase, and endopeptidase, were not inhibited at bactericidal concentrations of FL 1060 , but the formation of peptido-glycans covalently bound to the cell wall or to lipoproteins was impaired. 

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