Aspartate a-decarboxylase

ASPARTYLCLUCOSAMINIDASE ASPARTATE AMINOTRANSFERASE ASPARTATE AMMONIA-LYASE ASPARTATE CARBAMOYLTRANSFERASE ASPARTATE a-DECARBOXYLASE ASPARTATE /3-DECARBOXYLASE ASPARTATE KINASE d-ASPARTATE OXIDASE ASPARTATE RACEMASE... 

Histidine (bacterial) S-Adenosylmethionine Aspartate a- decarboxylase (3-Alanine... 

Aspartate a-decarboxylase 753, 755 Aspartate p-decarboxylase 746 Aspartate racemase 741 Aspartic acid (Asp, D) 52, 53s biosynthesis 517 pXa value of 293, 487 Aspartic proteases 621-625 Aspartyl aminopeptidase 621 p-Aspartyl phosphate 539, 540s Assays of enzyme activity 456 Assembly core of virus shell 365 Assembly pathway... 

In contrast to mammals, /i-alanine 3 is generated in Escherichia coli [12] mainly by decarboxylation of L-aspartate 4 [13] (Scheme 1.6.3). The tetrameric enzyme, l-aspartate-a-decarboxylase (EC 4.1.1.15), was isolated from E. coli [13], cloned [14], and its crystal structure [15] was determined. In bacteria, pantothenate synthase converts /(-alanine to pantothenate, a constituent of coenzyme A [16],... 

Glide docking into L-aspartate a-decarboxylase 333,761 compounds including Maybridge, ZINC, NCI, and FDA drugs were docked in the crystal structure and then narrowed to 703 hits and further limited to 28 and then eight compounds. No experimental validation was reported Sharma et al. (90)... 

L-aspartate-a-decarboxylase, which leads to the formation of p-alanine, and further nitrogenous products are formed, as shown in Fig. 15.2. 

Konst, P.M., Franssen, M.C.R., Scott, E.L., Sanders, J.P.M., 2009. A study on the applicability of L-aspartate a-decarboxylase in the biobased production of nitrogen containing chemicals. Green Chemistry 11, 1646-1652. 

Aspartic acid decarboxylase cataly2es the decarboxylation of asparatic acid to yield P-alanine (10), a precursor for the biosynthesis of pantothenic acid (67). FiaaHy, (R)-pantothenic acid is obtaiaed by coupling P-alaniae (10) with (R)-pantoate (22) ia the presence of pantothenate synthetase ... 

Amino Acid Systems Glutamine binding sites, 46, 414 labeling of the active site of r-aspartate /3-decarboxylase with yS-chloro-r-ala-nine, 46, 427 active site of r-asparaginase reaction with diazo-4-oxonorvaline, 46, 432 labeling of serum prealbumin with N-bro-moacetyl-L-thyroxine, 46, 435 a pyridoxamine phosphate derivative, 46, 441. 

Mechanisms of action of pyridoxal phosphate (a) in glutamate-oxaloacetate transaminase, and (b) in aspartate /3-decarboxylase. 

P. Strop, H. Gehring, J. N. Jansonius, and P. Christen, Conversion of aspartate aminotransferase into an L-aspartate /3-decarboxylase by a triple active-site mutation, J. Biol. Chem. 1999, 274, 31203-31208. 

A number of decarboxylase enzymes have been described as catalysts for the preparation of chiral synthons, which are difficult to access chemically (see Chapter 2).264 The amino acid decarboxylases catalyze the pyridoxal phosphate (PLP)-dependent removal of C02 from their respective substrates. This reaction has found great industrial utility with one specific enzyme in particular, L-aspartate-P-decarboxylase (E.C. 4.1.1.12) from Pseudomonas dacunhae. This biocatalyst, most often used in immobilized whole cells, has been utilized by Tanabe to synthesize L-alanine on an industrial scale (multi-tons) since the mid-1960s (Scheme 19.33).242-265 Another use for this biocatalyst has been the resolution of racemic aspartic acid to produce L-alanine and D-aspartic acid (Scheme 19.34). The cloning of the L-aspartate-P-decarboxylase from Alcaligenes faecalis into E. coli offers additional potential to produce both of these amino acids.266... 

For two transaminases the remaining unknown stereochemical parameter was determined by demonstrating an internal transfer of tritium (dialkyl amino acid transaminase) [28] or deuterium (pyridoxamine-pyruvate transaminase) [27] from the a-position of the substrate L-alanine to C-4 of the cofactor. Internal hydrogen transfer from the a-position of the substrate amino acid to C-4 of PLP has also been demonstrated for two of the abortive transamination reactions, those catalyzed by tryptophan synthase fi2 protein [32] and by aspartate-/8-decarboxylase [31]. In addition, the same phenomenon must occur in alanine transaminase, as deduced from the observation that the enzyme catalyzes exchange of the /8-hydrogens of... 

Although an earlier formulation had interpreted the kynureninase reaction in terms of an a,/5-elimination mechanism [142], the available evidence now points to a mechanism paralleling that of aspartate-/5-decarboxylase [141] as proposed by Braunstein [143]. No stereochemical studies have been reported on kynureninase, but some work has been done on aspartate-/5-decarboxylase. 

As summarized in Scheme II, PLP enzymes can catalyze replacements at the y-carbon of amino acids and eliminations of HY between C-fi and C-y. In mechanistic similarity to the aspartate-/3-decarboxylase reaction, in these processes the quinoid intermediate 1 loses a proton from C-/3, followed by elimination of an anionic group (Y ) from C-y, to generate the central intermediate PLP-vinylglycine, 4 (Scheme II). This species, the vinylogue of 1, can undergo a number of reactions. Addition of a new anionic group (Y ) and reversal of the reaction sequence constitutes the y-replacement reaction, as in cystathionine-y-synthase. On the other hand, in analogy to the protonation of 1 at C-a, 4 can be protonated at C-y,... 

Fig. 8.22 The biosynthesis of [R]-pantothenate in E. coli [112]. Enzymatic activities ADC, L-aspartate-1 -decarboxylase KPHM, a-ketopantoate hydroxymethyltransferase KPR, a-ketopantoate reductase PS, pantothenate synthase.

Other pyruvate-containing enzymes include aspartate /3-decarboxylase from Escherichia coli, the enzyme that catadyzes the formation of -alanine for the synthesis of pantothenic acid (Section 12.2.4) proline reductase from Clostridium sticklandiv, phosphatidylserine decarboxylase from E. coir, and phenyladamine amiinotramsferase from Pseudomonas fluorescens. Phospho-pamtetheinoyl cysteine decau boxylase, involved in the synthesis of coenzyme A (Section 12.2.1), amd S-adenosylmethionine decarboxylase seem to be the only mammadiam pyruvoyl enzymes (Snell, 1990). 

The combined utilization in a single reactor of both aspartase from Brevibacterium flavum and aspartate-P-decarboxylase from Pseudomonas dacunhae, thereby catalyzing the reaction from fumaric acid via L-aspartic acid to L-alanine (5), has also been developed by Mitsubishi 5. ... 

A continuous production system using immobilized Pseudomonas dacunhae cells with high L-aspartate 3-decarboxylase activity is currently under investigation [12]. The reaction proceeds as shown below. 

Two enzymes that catalyze electrophilic replacement reactions at are kyn-ureninase and aspartate jS-decarboxylase. In the case of the former enzyme, the replacement reaction at involves retention of configuration, and intramolecular tritium transfer is observed between C of kynurenine and the methyl group of the product alanine, consistent with a single-base mechanism (272) [Eq. (56)] ... 

Production of L-alanine by decarboxylation of L-aspartic acid under the action of the intracellular L-aspartate-P-decarboxylase in Pseudomonas dacunhae (Tanabe Seiyaku Co., Ltd). A 1000-liter pressurized column bioreactor can typically yield 5 tons of L-alanine per month. 

The decarboxylation of L-aspartic acid to L-alanine is catalysed by a pyridoxal-P-dependent j8-decarboxylase whose reaction mechanism is clearly different from that of the a-decarboxylases since the initial step probably involves C -H bond cleavage. The steric course at during the normal decarboxylation reaction has recently been shown [23b] to be inversion. In addition to this, however, the enzyme will also catalyse the decarboxylation of amino-malonic acid to glycine and Meister and coworkers [24,25] have shown that this process involves loss of the Si carboxyl group with overall retention at C . 

Aminomalonic acid is a substrate for aspartate /5-decarboxylase (EC 4.1.1.12). When (3R)- and (3S)-[3- C]aminomalonates were prepared from [3- C]-and [l- C]serines, respectively, and incubated with this enzyme, the 3-pro-R carboxyl group was lost (346). Since the decarboxylation had been shown to incorporate label into the 2-pro-S hydrogen of glycine (78), the decarboxylation was deemed to have occurred with retention of configuration. 

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