Bacterial esterases

The CCC instruments have even been used as enzymatic reactors to carry out enantioselective processes. Thus, the hydrolysis of 2-cyanocyclopropy 1-1,1-dicar-boxylic acid dimethylester including a bacterial esterase in the stationary phase was reported [131]. After 8 h, the procedure yielded the desired product automatically, without any extraction and with an 80 % e.e. 

Pelletier I, J Altenbuchner (1995) A bacterial esterase is homologous with non-haem haloperoxidases and displays brominating activity. Microbiology (UK) 141 459-468. 

Other enzymes capable of halogenation processes include a bacterial esterase from Pseudomonas fluorescens (2316), acid phosphatases from the bacteria Shigella flexneri and Salmonella enterica ser. typhimurium (2317), a lactonohydrolase from Acinetobacter calcoaceticus F46 (2318), and hydroperoxide halolyse from the marine diatom Stephanopyxis turris (2319). The biosynthesis of the ubiquitous methyl halides seems to involve methyl transferase enzymes, which have been isolated and purified in the plant Brassica oleracea (S -adenosyl-L-methionine ... 

Pelletier I, Altenbuchner J (1995) A Bacterial Esterase is Homologous with Non-Haem Haloperoxidases and Displays Brominating Activity. Microbiology 141 459... 

Here are some selected examples of research studies which did not consider the above postulates. In 1949 a paper was published which reported inhibitions of bacterial esterases by chloramphenicol11J. No thought was given to the requirement that the inhibited reaction must be vitally important to growth of susceptible cells. 

Thermal and mechanical properties of several of the copolymers have been reported [35,36]. Biodegradation of these polymers by bacterial esterases yield monomers, dimers and trimers split off from the hydroxyl-terminal of the polymer chain. 

Doi et alP reported on the biodegradation of PHAs. The mechanism of biodegradation of these polymers has been studied and involves the enzyme, bacterial esterases, which depolymerizes the polymer to monomers, dimers, and trimers. Budwill et al reported the rapid mineralization of PHB and PHBV in anaerobic sewage sludge, and more than 90% metabolized to methane and... 

Britt AJ, NC Bruce, CR Lowe (1992) Identification of a cocaine esterase in a strain of Pseudomonas maltophilia. J Bacterial 174 2087-2094. 

The i-poly(3HB) depolymerase of R. rubrum is the only i-poly(3HB) depolymerase that has been purified [174]. The enzyme consists of one polypeptide of 30-32 kDa and has a pH and temperature optimum of pH 9 and 55 °C, respectively. A specific activity of 4 mmol released 3-hydroxybutyrate/min x mg protein was determined (at 45 °C). The purified enzyme was inactive with denatured poly(3HB) and had no lipase-, protease-, or esterase activity with p-nitro-phenyl fatty acid esters (2-8 carbon atoms). Native poly(3HO) granules were not hydrolyzed by i-poly(3HB) depolymerase, indicating a high substrate specificity similar to extracellular poly(3HB) depolymerases. Recently, the DNA sequence of the i-poly(3HB) depolymerase of R. eutropha was published (AB07612). Surprisingly, the DNA-deduced amino acid sequence (47.3 kDa) did not contain a lipase box fingerprint. A more detailed investigation of the structure and function of bacterial i-poly(HA) depolymerases will be necessary in future. 

Modifications of the arylamino moiety profoundly influence the rate of hydrolysis. Thus, the hydrolysis of N- ace ty 1 -4-am i no be n zo i c acid was ca. 1000-fold slower than that of acetanilide [66]. Sorci and Macalady [67] investigated the influence of ring substitution on the hydrolysis of para-substituted acetanilides (4.104) in alkaline solution and in soil bacteria. No correlation was found between alkaline and biotic hydrolysis, which appeared to be controlled by different physicochemical properties. Bacterial hydrolysis was best correlated with the Van der Waals radius of the substituent, whereas chemical hydrolysis was correlated with the Hammett constant characterizing the electron-withdrawing capacity of the substituent. Other studies confirmed that a correspondence between bacterial and mammalian esterases... 

FIGURE 5 Relative scopes (measured as quartile range/median) for an array of extracellular enzymes and for bacterial production and respiration. Dependent variables shown along the X-axis are (left to right) leucine aminopeptidase, phosphatase, fatty acid esterase, (3-glucosidase, a-glucosidase, bacterial production, and bacterial respiration. Data are derived from four DOM experimental amendments. 

The roles of enteric bacterial sialidase, sialate O-acetyl esterase and glycosulfatase in the degradation of human colonic mucin. Glycoconj J 10, 72-81... 

Resistance to erythromycin is becoming a serious clinical problem. For example, most strains of staphylococci in hospital isolates are resistant to this drug. Several mechanisms have been identified (1) the inability of the organism to take up the antibiotic (2) a decreased affinity of the 50S ribosomal subunit for the antibiotic resulting from the methylation of an adenine of the 23S bacterial ribosomal RNA and (3) presence of a plasmid-associated erythromycin esterase. Both clarithromycin and azithromycin show cross-resistance with erythromycin. 

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