Mycobacterium neoaurum

Sharman GJ, Williams DH, Ewing DE, Ratledge C (1995) Determination of the Structure of Exochelin MN, the Extracellular Siderophore from Mycobacterium neoaurum. Chem Biol 2 553... 

Lehr et al. (2003) found that Mycobacterium neoaurum could demethylate MMA(III) and MMA(V) to inorganic arsenic, but not DMA(V) or trimethylarsine oxide. Their results suggest that at least some MMA(V) reductively demethylates to inorganic As(III), which is a reversal of Reaction 2.13 (see above) in the Challenger mechanism (Lehr et al., 2003), 833. Other mechanisms by which microorganisms demethylate arsenic are largely unknown (Lehr et al., 2003). Chapter 4 presents additional information on the demethylation of arsenic. 

Lee, J.S. and Nriagu, J.O. (2007) Stability constants for metal arsenates. Environmental Chemistry, 4(2), 123-33. Lehr, C.R., Polishchuk, E., Radoja, U. and Cullen, W.R. (2003) Demethylation of methylarsenic species by Mycobacterium neoaurum. Applied Organometallic Chemistry, 17(11), 831-34. 

A)-alcohol (7) by Sphingomonas paucimobilis SC 16113 (Fig. 6) (2) the enzymatic resolution of racemic (a-methyl)phenylalanine amide (8) and a-(4-methoxyphenyl)alanine amide (10) by amidase from Mycobacterium neoaurum ATCC 25795 to prepare the corresponding (S)-amino acids (9) and (11), and (3) the asymmetric hydrolysis of methyl-(4-methoxyphenyl)-propanedioic acid, diethyl ester (12), to the corresponding (X)-monoester (13) by pig liver esterase (Fig. 7). 

As a biocatalyst that is capable of converting a,a-disubstituted amino acids efficiently, an aminopeptidase in the strain Mycobacterium neoaurum [ATCC 25795]... 

Permeabilized whole cells of Mycobacterium neoaurum ATCC 25795 or crude enzyme preparations can be used. 

Table 12.2-3. Substrate specificity of the amidase activity of Mycobacterium neoaurum cells.

Enzymatic Resolution of Racemic a-Methyl Phenylalanine Amides. The chiral amino acids (22) and (23) (Fig. 6A) are intermediates for the synthesis of (33-receptor agonists (30,31). These are available via the enzymatic resolution of racemic a-methyl phenylalanine amide (24) and a-methyl-4-methoxy-phenylalanine amide (25), respectively, by an amidase from Mycobacterium neoaurum ATCC 25795 (32). Wet cells (10% wt/vol) completed the reaction of amide (24) in 75 min with a... 

DSM has also succeeded in reacting a-branched amino acid amides with peptidases from Mycobacterium neoaurum. By this method, compounds such as the antihypertonic (L)-a-methyl-3,4-dihydroxyphenylalanine ((L)-a-methyl-DOPA) are accessible. For very similar transformations, Ube (Japan) has used amidases from Pseudomonasfluorescens. [64]... 

In this chapter we describe the DSM aminoamidase processes in more detail. Three different enzymatic resolution routes have been developed for the preparation of natural and synthetic amino acids using biocatalysts from different origin, i.e.. Pseudomonas pu-tida, Mycobacterium neoaurum, and Ochrobactrum anthropi. Scope and limitations and enzyme characterization of these amidases will be presented together with some specific examples. In addition, the use of some of these amino acids in peptide sjmthesis, catalytic asymmetric synthesis, and further synthetic transformations will be given. 

III. AMINO AMIDASE FROM MYCOBACTERIUM NEOAURUM ATCC 25795... 

Identically to the enz5miatic resolution process for a-H-amino acid amides by P. putida, we searched for a new biocatalyst for the stereoselective hydrolysis of a,a-disub-stituted amino acid amides (15). Through screening a new biocatalyst Mycobacterium neoaurum ATCC 25795 was obtained that fulfilled the demand for stereoselective hydrolysis [43,44]. 

C. Resolution of a,a-Disubstituted Amino Acid Amides Using Whole Cells of Mycobacterium neoaurum... 

L-a-Amino acids have been prepared by the resolution of racemic a-amino acid amide by the L-specific aminopeptidase from Pseudomonas putida ATCC 12633 [7]. Enzyme from R putida ATCC 12633 cannot be used to resolve a-alkyl-substituted amino acid amides 103. Aminoamidase from Mycobacterium neoaurum ATCC 25795 has been used in the preparation of L-a-alkyl amino acid 104 (Fig. 34) and D-amide of a-alkyl-substituted amino acids by enzjmaatic resolution process using racemic a-alkyl amino acid amide as a substrate [169,179]. Amidase from Ochrobactrum anthropi catalyzed the resolution of a,a-disubsituted amino acids, iV-hydroxy amino acids, and a-hydroxy acid amides. The resolution process could lead to the production of chiral amino acids or amides in 50% yield. Recently, amino acid racemases have been used to get 100% yield of chiral amino acids [179]. 

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