Enzyme rhodococcus

A very simple and elegant alternative to the use of ion-exchange columns or extraction to separate the mixture of D-amino add amide and the L-amino add has been elaborated. Addition of one equivalent of benzaldehyde (with respect to die D-amino add amide) to the enzymic hydrolysate results in the formation of a Schiff base with die D-amino add amide, which is insoluble in water and, therefore, can be easily separated. Add hydrolysis (H2SQ4, HX, HNO3, etc.) results in the formation of die D-amino add (without racemizadon). Alternatively the D-amino add amide can be hydrolysed by cell-preparations of Rhodococcus erythropolis. This biocatalyst lacks stereoselectivity. This option is very useful for amino adds which are highly soluble in die neutralised reaction mixture obtained after acid hydrolysis of the amide. 

Enantioselective transformations of several cyclopropane or oxirane-containing nitriles were studied using nitrile-transforming enzymes [78]. Microbial Rhodococcus sp. whole cells containing a nitrile hydratase/amidase system hydrolyzed a number... 

The dehydration reaction of aldoxime to form nitriles using the resting cells of Rhodococcus sp. YH3-3 was optimized. We found that the enzyme was induced by aldoxime and catalyzed the stoichiometric synthesis of nitriles from aldoximes at pH 7.0 and 30°C. Phenylacetonitrile once synthesized from phenylacetaldoxime was hydrolyzed to phenylacetic acid, since the strain has nitrile degradation enzymes such as nitrile hydratase and amidase. We have been successful in synthesizing phenylacetonitrile and other nitriles stoichiometrically by a selective inactivation of nitrile hydratase by heating the cells at 40°C for 1 h. Various nitriles were synthesized under optimized conditions from aldoximes in good yields. 

The NHase responsible for aldoxime metabolism from the i -pyridine-3-aldoxime-degrading bacterium, Rhodococcus sp. strain YH3-3, was purified and characterized. Addition of cobalt ion was necessary for the formation of enzyme. The native enzyme had a Mr of 130000 and consisted of two subunits (a-subunit, 27 100 (3-subunit, 34500). The enzyme contained approximately 2 mol cobalt per mol enzyme. The enzyme had a wide substrate specificity it acted on aliphatic saturated and unsaturated as well as aromatic nitriles. The N-terminus of the (3-subunit showed good sequence similarities with those of other NHases. Thus, this NHase is part of the metabolic pathway for aldoximes in microorganisms. 

The enzyme in Rhodococcus sp. strain IGTS8 that brings about successive oxidation of dibenzothiophene to the sulfoxide and the sulfone is a flavin mononucleotide-dependent monooxygenase that carries out both reactions by sequential incorporation of a single atom of oxygen from Oj (Lei and Tu 1996). 

Lei B, S-C Tu (1996) Gene overexpression, purification, and identification of a desulfurization enzyme from Rhodococcus sp. strain IGTS8 as a sulfide/sulfoxide monooxygenase. J Bacteriol 178 5699-5705. 

The metabolism of 2-methylquinoline in Arthrobacter sp. strain Rii 61a is comparable, with introduction of oxygen at C4 (Hund et al. 1990). The enzymes (oxidoreductases) that introduce oxygen into the azaarene rings in Rhodococcus sp. strain Bl, Arthrobacter sp. strain Rii61a, and Pseudomonas putida strain 86 are virtually identical and, like those already noted have molecular masses of 300-320 kDa and contain Mo, Fe, FAD, and acid-labile sulfur (De Beyer and Lingens... 

The enantiomeric reduction of 2-nitro-l-phenylprop-l-ene has been studied in a range of Gram-positive organisms including strains of Rhodococcus rhodochrous (Sakai et al. 1985). The enantiomeric purity of the product depended on the strain used, the length of cultivation, and the maintenance of a low pH that is consistent with the later results of Meah and Massey (2000). It has been shown that an NADPH-linked reduction of a,p-unsaturated nitro compounds may also be accomplished by old yellow enzyme via the flcf-nitro form (Meah and Massey 2000). This is formally analogous to the reduction and dismutation of cyclic enones by the same enzyme (Vaz et al. 1995), and the reductive fission of nitrate esters by an enzyme homologous to the old yellow enzyme from Saccharomyces cerevisiae (Snape et al. 1997). 

In another approach, the alcohol moiety, formed by an enzymatic hydrolysis of an ester, can act as a nucleophile. In their synthesis of pityol (8-37a), a pheromone of the elm bark beetle, Faber and coworkers [17] used an enzyme-triggered reaction of the diastereomeric mixture of ( )-epoxy ester 8-35 employing an immobilized enzyme preparation (Novo SP 409) or whole lyophilized cells of Rhodococcus erythro-polis NCIMB 11540 (Scheme 8.9). As an intermediate, the enantiopure alcohol 8-36 is formed via kinetic resolution as a mixture ofdiastereomers, which leads to the diastereomeric THF derivatives pityol (8-37a) and 8-37b as a separable mixture with a... 

The activities of NHases from Rhodococcus sp. Adpl2 and Gordonia sp. BR-1 strains have been partially characterized [25]. In reactions that catalyze the hydration of a-hydroxynitriles such as lactonitrile or glycolonitrile, the substrate can dissociate to produce HCN and the corresponding aldehydes. HCN can inhibit and/or inactivate NHase, and it was determined that these two enzymes remain active in the presence of cyanide ion at concentrations up to 20 him. The dependence of the NHase activity of cell-free extracts of Rhodococcus rhodochrous J1 and Gordonia sp. BR-1 on cyanide ion concentration is illustrated in Figure 8.1, demonstrating the improved cyanide stability of BR-1 NHase relative to that of Jl. 

Rhodococcus erythropolis NCIMB 11540 has been employed as biocatalyst for the conversion of (R)- or (.S )-cyanohydrins to the corresponding (R)- or (S)-a-hydroxycarboxylic acids with an optical purity of up to >99% enatiomeric excess (ee) [27-29] the chiral cyanohydrins can separately be produced using hydroxynitrile lyase from Hevea braziliensis or from Prunus anygdalis [30]. Using the combined NHase-amidase enzyme system of the Rhodococcus erythropolis NCIMB 11 540, the chiral cyanohydrins were first hydrolyzed to the... 

Yeom, S.-J., Kim, H.-J. and Oh, D.-K. (2007) Enantioselective production of 2,2-dimethylcyclopropane carboxylic acid from 2,2-dimethylcyclopropane carbonitrile using the nitrile hydratase and amidase of Rhodococcus erythropolis ATCC 25544. Enzyme and Microbial Technology, 41, 842-848. 

Guo, X.-L., Deng, G., Xu, J. and Wang, M.-X. (2006) Immobilization of Rhodococcus sp. AJ270 in alginate capsules and its application in enantioselective biotransformation of ira/i.s-2-methyl-3- phenyl-oxiranecarbonitrile and amide. Enzyme and Microbial Technology, 39, 1-5. 

The 3-ketothiolase has been purified and investigated from several poly(3HB)-synthesizing bacteria including Azotobacter beijerinckii [10], Ral-stonia eutropha [11], Zoogloea ramigera [12], Rhodococcus ruber [13], and Methylobacterium rhodesianum [14]. In R. eutropha the 3-ketothiolase occurs in two different forms, called A and B, which have different substrate specificities [11,15]. In the thiolytic reaction, enzyme A is only active with C4 and C5 3-ketoacyl-CoA whereas the substrate spectrum of enzyme B is much broader, since it is active with C4 to C10 substrates [11]. Enzyme A seems to be the main biosynthetic enzyme acting in the poly(3HB) synthesis pathway, while enzyme B should rather have a catabolic function in fatty-acid metabolism. However, in vitro studies with reconstituted purified enzyme systems have demonstrated that enzyme B can also contribute to poly(3HB) synthesis [15]. 

IGTS8 or simply IGTS8. The metabolic pathway in Rhodococcus sp. IGTS8 was delineated in the early 1990s [62], The pathway consists of four enzymes. DBT is converted to 2-hydroxybiphenyl (HBP) and sulfite via a 4-step pathway and the following intermediates DBT sulfoxide (dibenzothiophene-5-oxide, DBTO), DBT sulfone (dibenzothiophene-5,5-dioxide, DBT02) and hydroxyphenyl benzene sulfonate (phenol-phenyl sulfinate, HBPSi). 

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