A Biocatalytic Route to Enantiomerically Pure Unsaturated α-H-α-Amino Acids

Wolf, Larissa B.; Sonke, Theo; Tjen, Kim C. M. F.; Kaptein, Bernard; Broxterman, Quirinus B.; Rutjes, Floris P. J. T.

doi:10.1002/1615-4169(200108)343:6/7<662::aid-adsc662>3.0.co;2-i

Cited by 37 publications

(18 citation statements)

References 8 publications

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“…An important advantage of this novel whole-cell biocatalyst became manifest in the preparation of a set of enantiopure unsaturated a-H-a-amino acids ( Figure 15.2) [222]. In general, the resolution of these unsaturated amino acid amides with the recombinant E. coli based system as well as with the wild-type P. putida cells proceeded smoothly, yielding the L-acid and the D-amide in high enantiomeric excess (>95%) at 50% conversion.…”

Section: Synthesis Of Enantiopure A-h-a-amino Acidssupporting

confidence: 86%

Hydrolysis of Amides

Sonke

Kaptein

2012

Enzyme Catalysis in Organic Synthesis

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Section: Synthesis Of Enantiopure A-h-a-amino Acidssupporting

confidence: 86%

Hydrolysis of Amides

Sonke

Kaptein

2012

Enzyme Catalysis in Organic Synthesis

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“…Examples include the production of both enantiomers of the ␣,␣-disubstituted ␣-hydroxy acid 3,3,3-trifluoro-2-hydroxy-2-methylpropionic acid using an amidase from Klebsiella oxytoca PRS1 (12,43), the synthesis of the cyclic ␣-hydrogen-␣-amino acid (S)-piperazine-2-carboxylic acid by an amidase from Klebsiella terrigena DSMZ 9174 (21) and by the leucine aminopeptidase from porcine kidney (13), the use of a D-amidase from Variovorax paradoxus DSMZ 14468 for the synthesis of aliphatic ␣-hydrogen-␣-amino acids such as D-leucine and D-tert-leucine (35,52), and the lab-scale synthesis of both enantiomeric forms of a set of unsaturated ␣-hydrogen-␣-amino acids using the leucine aminopeptidase from Pseudomonas putida ATCC 12633 (55).…”

Section: Discussionmentioning

confidence: 99%

l-Selective Amidase with Extremely Broad Substrate Specificity fromOchrobactrum anthropiNCIMB 40321

Sonke¹,

Ernste²,

Tandler³

et al. 2005

Appl Environ Microbiol

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An industrially attractive L-specific amidase was purified to homogeneity from Ochrobactrum anthropi NCIMB 40321 wild-type cells. The purified amidase displayed maximum initial activity between pH 6 and 8.5 and was fully stable for at least 1 h up to 60°C. The purified enzyme was strongly inhibited by the metal-chelating compounds EDTA and 1,10-phenanthroline. The activity of the EDTA-treated enzyme could be restored by the addition of Zn 2؉ (to 80%), Mn 2؉ (to 400%), and Mg 2؉ (to 560%). Serine and cysteine protease inhibitors did not influence the purified amidase. This enzyme displayed activity toward a broad range of substrates consisting of ␣-hydrogen-and (bulky) ␣,␣-disubstituted ␣-amino acid amides, ␣-hydroxy acid amides, and ␣-N-hydroxyamino acid amides. In all cases, only the L-enantiomer was hydrolyzed, resulting in E values of more than 150. Simple aliphatic amides, ␤-amino and ␤-hydroxy acid amides, and dipeptides were not converted. The gene encoding this L-amidase was cloned via reverse genetics. It encodes a polypeptide of 314 amino acids with a calculated molecular weight of 33,870. Since the native enzyme has a molecular mass of about 66 kDa, it most likely has a homodimeric structure. The deduced amino acid sequence showed homology to a few other stereoselective amidases and the acetamidase/ formamidase family of proteins (Pfam FmdA_AmdA). Subcloning of the gene in expression vector pTrc99A enabled efficient heterologous expression in Escherichia coli. Altogether, this amidase has a unique set of properties for application in the fine-chemicals industry.Enantiomerically pure ␣-amino acids, both natural and unnatural, form an important class of chiral building blocks for the pharmaceutical and agrochemical industries. Examples of important ␣-hydrogen-␣-amino acids are D-phenylglycine (DPhg) and D-p-hydroxyphenylglycine, which are produced as side chains for the manufacture of semisynthetic ␤-lactam antibiotics such as ampicillin, amoxicillin, and cephalexin (14, 53), and D-valine, an intermediate for the pyrethroid insecticide fluvalinate (28). Another frequently used ␣-hydrogen-␣-amino acid is L-tert-leucine, which is used as a building block for a variety of antiviral (e.g., anti-human immunodeficiency virus), antiarthritis, and anticancer drugs under development and as a chiral auxiliary in chemical asymmetric synthesis (5, 10). Besides ␣-hydrogen-␣-amino acids, ␣,␣-disubstituted ␣-amino acids also constitute a group of compounds of increasing importance, as exemplified by the use of L-␣-methyl-3,4-dihydroxyphenylalanine (L-␣-methyldopa) as an antihypertensive drug (34, 42), ␣-methylvaline as an intermediate for the herbicide Arsenal and related herbicides (47, 49), and L-␣-methylphenylglycine as a building block for the new fungicide fenamidone (27).Enantiomerically pure ␣-amino acids can be produced on a commercial scale by a number of different processes, both chemical and enzymatic. Biocatalytic processes that have been commercialized include the acylase process operated by Degussa (8) a...

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“…The obtained pellet was dried overnight in a vacuum dessicator to give 4.1 g of crude amino acid 1. The combined aqueous layers were evaporated to dryness and the residue was treated with a cation exchange resin (Dowex (RS)-N-(9-fluorenylmethyloxycarbonyl)-2-amino-5-hexynoic acid (Fmoc-Bug-OH) rac-4: To a suspension of K 2 CO 3 (836 mg, 6.03 mmol) in CH 3 CN (10 mL), tetrabutylammonium bromide (21 mg, 0.01 eq) followed by methyl N-(diphenylmethy1ene)-glycinate 6,7 (508 mg, 2 mmol) were added. After stirring for 20 min, 1-bromo-2-butyne (186 _L, 2 mmol, 1 eq) was added dropwise and the reaction S5 mixture was refluxed overnight.…”

Section: S4mentioning

confidence: 99%