Alanine serine synthesis

In summary, ring opening of serine-3-lactones is an attractive method for generating optically pure 3-substituted alanines the synthesis usually occurs with little or no epimerization. 

SYNTHESIS OF N-PROTECTED a-AMINO ACIDS FROM N-(BENZYLOXYCARBONYL)-L-SERINE VIA ITS p-LACTONE N -(BENZYL0XYCARB0NYL)-P-(PYRAZ0L-1-YL)-L-ALANINE (Serine, N-carboxy-, p-iactone, benzyl ester, L-)... 

Figure 7 Localization of cell wall synthesis in isogenic pairs of vancomycin-susceptible and vancomycin-resistant Staphylococcus aureus strains. Images show labeling of JH1/JH9 (susceptible) and COL/VM50 (resistant) cells with a fluorescent vancomycin derivative, after growth with an excess of o-serine (synthesis of older peptidoglycan with D-Ala-D-ser termini, to which the labeled vancomycin cannot bind) followed by transient incubation with o-Alanine, which results in n-Ala incorporation into new peptidoglycan, to which the vancomycin can bind. In all cases, the main location for cell wall synthesis is at the division septum. Data reproduced from P. M. Pereira S. R. Filipe A. Tomasz M. G. Pinho, Antimicrob. Agents Chemother. 2007, 51 (10), 3627, with permission from the American Society for Microbiology.

They catalyse rate-limiting steps in the pathway and are important control points. Glucogenic intermediates of the tricarboxylic acid cycle and amino acids that are transaminated or deaminated to tricarboxylic acid intermediates do not require pyruvate carboxylase (Fig. 3.1). Pyruvate and metabolites such as lactate, alanine, serine, glycine, cysteine that are converted into pyruvate require all four enzymes (Fig. 3.1). Gluconeogenesis is often linked to glycogen synthesis catalysed by glycogen synthase (see Section 3.5). 

Non-essential amino acid Those amino acids which are required for protein synthesis but can be synthesized in the body in adequate amounts to meet requirements and therefore do not have to be provided in the diet. The non-essential amino acids are glycine, alanine, serine, proline, glutamic acid, aspartic acid, glutamine, asparagine and arginine. In addition, tyrosine can be synthesized in the body, but only from the essential amino acid phenylalanine, and cysteine can be synthesized, but only from the essential amino acid methionine. 

Pyruvate dehydrogenase produces acetyl CoA which can be used in synthesis of FAs. Enoyl CoA hydratase is an enzyme of the p-oxidation pathway and does not produce acetyl CoA. The three glycogenic amino acids are alanine, serine and glycine they cannot be directly converted to acetyl CoA. The ketogenic amino acid isoleucine may be converted directly to acetyl CoA. Cholesterol is synthesized from acetyl CoA. However, cholesterol cannot be degraded in the body and is disposed of by excretion in bile. 

The amino acids derived from pyruvate or 3-phosphogIycerate include alanine, serine, and glycine. Synthesis of these amino acids can be achieved by multiple pathways involving several different subcellular compartments. Although enzymes that could contribute to their biosynthesis are easily demonstrable in plants (Miflin and Lea, 1982), the relative contribution of each potential pathway may vary from species to species, and within a single organism in different tissues or under different physiological conditions. 

The extension to amino acid synthesis on surfaces has also been observed with platinised Ti()2 surfaces, with CH4, NH3 and H20 solutions producing glycine, alanine, glutamine, aspartic acid and serine, all photosynthesised and trapped in the resulting layers near to the surface by their charge. 

The solid-phase synthesis of glycopeptides was first realized by applying the polymeric benzyl ester principle of Merrifield. According to this methodology, Lavielle and associates (50) used 7V-(tm-butyloxycarbonyl)-<9-glycosyl serine derivative 153 for condensation with resin-linked alanine 154. 

The non-essential amino acids are alanine, arginine, aspartate, asparagine, cysteine, glutamate, glutamine, glycine, proline, serine and tyrosine. A summary of the reactions involved in their synthesis is given in Figure 8.3 and full details of these pathways are provided in Appendix 8.2. 

Synthesis of N-Protected a-Amino Acids from N-(Benzyloxycarbonyl)-L-Serine via Its g-Lactone N -(Benzyloxycarbonyl)-p-(Pyrazol-1-yl)-L-Alanine... 

Enantiopure (5)-fluoroalanine has been prepared by an enzymatic path starting from 3-fluoropyruvate in the presence of alanine dehydrogenase, and also by chemical synthesis from (5)-p-tolyl methyl sulfoxide (Figure 5.1) or from the L-serine. The analogue labeled with F has been prepared for use in positron emission tomography (PET) used in cancer diagnosis. ... 

H N C00R= Alanine, leucine, serine, tyrosine, methionine, proline, etc. Figure 5.5 Synthesis of trifluoroalanine-containing dipeptides. 

An enantioselective synthesis of ferrocenyl-modified alanines 91 and 93 was also reported.163 In this case, an organozinc derivative of serine 90 was coupled to iodoferrocene 89 or 1,1 -diiodoferrocene 92 using a palladium catalyst [Pd2(dba)3] to give the Boc-ferrocenyl-L-ala-nine methyl esters 91 and 93 in 60 and 64% yield, respectively (Scheme 26). 

In 1959 Shchukina et a I. 56 showed that the addition of pyridine to DCC increases the yield (65-85%) of depsipeptides constructed from Z-protected amino acids and serine, threonine, or salicylic acid derivatives. The ferf-butyl ester of Af-(benzyloxycarbonyl)-leucylleucic acid (Table 2) was prepared in 60% yield under the same conditions of addition using a 2 molar excess of pyridine to carbodiimide. 57 The DCC/pyridine technique was successfully utilized in the ring closure between ()-alanine and leucic acid residues during the synthesis of the cyclic hexadepsipeptide destruxin B.[58 Under this modified approach the... 

Four of the amino acids, alanine, aspartate, glutamate, and serine, are formed by the transamination of their corresponding oxoacids. The other nonessential amino acids are then derived from these four amino acids. The syntheses of serine and tyrosine are described below because of either their importance in aspects of metabolism or their clinical significance the synthesis of serine is essential for folic acid metabolism, while deficiencies in the enzymes synthesizing tyrosine can lead to phenylketonuria. 

By contrast, the amino acid compositions of the two forms of inver-tase (internal and external) differ significantly in the number of residues of certain amino acids. These differences occur notably in the content of serine, alanine, cystine, methionine, tyrosine, lysine, and histidine. The significance of these differences is not yet apparent, but these two invertases are obviously not isoglycoenzymes. The synthesis of proteins having such diverse amino acid compositions as have the two invertases would probably necessitate two separate genetic-control mechanisms. 

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