Lactobacillus brevis alcohol dehydrogenase

For reduction of acetylenic ketones, two oxidoreductases were used [25]. Lactobacillus brevis alcohol dehydrogenase (LBADH) gave the (R)-alcohols and Candida parapsilosis carbonyl reductase (CPCR) afforded the (S)-isomer, both in good yield and excellent enantioselectivity. By changing the steric demand of the substituents, the enantiomeric excess values can be adjusted and even the configurations of the products can be altered (Figure 8.34). 

As part of the chemoenzymatic synthesis of (/ )-(-)-rhododendrol, Cacchi and co-workers used perfluorotagged Pd NPs, immobilized on fluorous silica gel in the Mizoroki-Heck reaction of 4-iodophenol and 3-hydro>y-l-butene to synthesize the key intermediate 4-(4-hydro y-phenyl)butan-2-one (more commonly known as raspberiy ketone) in one step. The coupling product was further treated with the Lactobacillus brevis alcohol dehydrogenase (LMDH) in 2-propanol to give (/ )-rhodo-dendrol in 90% conversion and 99% ee (Scheme 4). 

The highly enantiosdective reduction of 2-octanone catalyzed by Lactobacillus brevis alcohol dehydrogenase is faster in a biphasic system containing buffer and the ionic liquid [BMIM][(CF(3)SO(2))(2)N] compared to the reduction in a biphasic system containing buffer and methyl tert-butyl ether due to favorable partition coefficients (Figure 3.24) [33]. 

Lactobacillus brevis whole-cell biotransformation When the reduction of diketo ester la was performed with whole cells of Lactobacillus brevis or L. kefir, formation of the 3,5-dihydroxy ester (3R,5S)-5a was observed [10, 22]. This was surprising since it is known that the prevailing alcohol dehydrogenase in I. brevis is the one described as LBADH [23] and since, moreover, this enzyme does not reduce P-keto 5-hydroxy ester 2a to the corresponding dihydroxy ester (Scheme 2.2.7.6). Under the conditions tested, further alcohol dehydrogenase activity is clearly present in I. brevis and I. kefir. Pfruender et al. optimized the production of L. kefir cells and used this biocatalyst for the one-pot synthesis of dihydroxy ester syn-(3R,5S)-5a using diketo ester la as starting material [24]. 

The crystal structure of R-spedfic alcohol dehydrogenase from Lactobacillus brevis suggests the structural basis of its metal dependency, J. Mol. Biol. 2003, 327, 317-328. 

W. Hummel, and D. Schomburg, Crystallization and preliminary characterization of crystals of R-alcohol dehydrogenase from Lactobacillus brevis, Acta Crystallogr D Biol Crystallogr. 2000, 56, 1696-1698. 

Another way to statin side chains, via the intermediate syn-(i K,5,S )-6-chloro-hexanoate, employs regioselective and (K)-specific reduction with alcohol dehydrogenase (ADH) from Lactobacillus brevis to yield the intermediate (5S)-6-chloro-3-ketohexanoate from the 3,5-diketo acid (Wolberg, 2001) (Figure 13.16). Further reduction of (5S)-6-chloro-3-ketohexanoate to syn-(3R,5S)-6-chlorohexanoate is afforded chemically with NaBH4/B(OMe)Et2. 

Purification of Alcohol Dehydrogenase from Lactobacillus brevis.168... 

Table 12. Purification of alcohol dehydrogenase from Lactobacillus brevis. (Phenyl-and octylsepharoses are materials for hydrophobic interaction chromatography Mono Q is an anionic exchanger.)...

Table 13. Substrate specificity of alcohol dehydrogenase from Lactobacillus brevis ...

Fig. 4. DNA and protein sequence of the recombinant (R)-alcohol dehydrogenase from Lactobacillus brevis in E. coli (upper line DNA sequence lower line corresponding amino acid in one letter code). The sequences of the primers are given in bold-type, sequences obtained by amino acid sequencing are underlined...

Hydroxyhept-6-enoates have been key intermediates in the synthesis of a variety of natural products, especially of the arachidonic acid metabolic pathway, including prostaglandins, leukotrienes, and isoprostanes [105, 113-118]. The usage of two enantiocomplementary enzymes allowed convenient access to both enantiomers via an ADH-catalyzed reduction of 5-oxo-hept-6-enoate. Alcohol dehydrogenase from Lactobacillus brevis (ADH-LB) furnished the (S )-enantiomer, Thermoanaerobacter sp. ADH (ADH-T) the (7 )-enantiomer in excellent enantiomeric access respectively [119]. A cross-metathesis reaction followed by cyclopropanation led to the formal synthesis of constanolactones C and D (Fig. 16) [86, 120, 121]. 

The alcohol dehydrogenase from Lactobacillus brevis was used to catalyze the enantioselective reduction of 2-octanone to (i )-2-octanol on the expense of the reduced cofactor NADPH. The same enzyme is able to regenerate NADPH from... 

F. Hildebrand, S. Lutz, Immobilisation of alcohol dehydrogenase from Lactobacillus brevis and its application in a plug flow reactor. Tetrahedron Asymm. 17 (2006) 3219-3225. 

However, this approach fails for the synthesis of the complementary (1S,2S)-NPE and (1S,21 )-NE since no enzyme is known to provide (S)-PAC in high optical purity. As an alternative, an co-TA/alcohol dehydrogenase (ADH) reaction sequence has been investigated in a recent report. The reaction sequence comprises an (S)-selective co-TA (CV co-TA) with an (P)-selective ADH from Ralstonia sp. (R-ADH) or the (S)-selective ADH from Lactobacillus brevis (LB-ADH) (Scheme 2.16) [83]. The cascade has to be performed in a sequential mode due to the divergent reaction conditions required for each step. Besides, deactivation of the co-TA before the ADH-catalyzed step was mandatory to avoid the formation of l-phenylpropane-l,2-diol. At 10 mM substrate concentration, the system yielded (1S,2S)-NPE and (1S,2R)-NE in moderate to high conversions and perfect optical purity when pure enz5unes were used as catalysts. 

Useful intermediates for the synthesis of a variety of arachidonic acid metabolites were prepared (Figure 11.10a). (R)-5-Hydroxyhept-6-enonoate was obtained from the reduction of ethyl 5-oxo-6-heptenoate by Thermoanaerobacter sp. alcohol dehydrogenase (ADH) expressed in E. coli [56]. The opposite enantiomer, (S)-5-hydroxyhept-6-enonoate, was obtained by using Lactobacillus brevis ADH. These chiral alcohols are important intermediates for prostaglandins, leukotrienes, isoprostanes, and atractyligenin. 

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