Enzymes expression

Optimizing pectinolytic enzyme expression Promoter gene fusions... 

Hummel, W., Abokitse, K., Drauz, K. et al. (2003) Towards a large-scale asymmetric reduction process with isolated enzymes Expression of an (5)-alcohol dehydrogenase in E. coli and studies on the synthetic potential of this biocatalyst. Advanced Synthesis and Catalysis, 345 (1 + 2), 153-159. 

From the above, it is clear that the gut wall represents more than just a physical barrier to oral drug absorption. In addition to the requirement to permeate the membrane of the enterocyte, the drug must avoid metabolism by the enzymes present in the gut wall cell as well as counter-absorptive efflux by transport proteins in the gut wall cell membrane. Metabolic enzymes expressed by the enterocyte include the cytochrome P450, glucuronyltransferases, sulfotransferases and esterases. The levels of expression of these enzymes in the small intestine can approach that of the liver. The most well-studied efflux transporter expressed by the enterocyte is P-gp. 

The properties listed are for recombinant DszB enzyme expressed in E. coli. The original enzyme from R. erythropolis could not be isolated due to its low yield from the native host. 

Further research in improving the BDS activity of the biocatalysts was targeted towards the search of co-catalysts and co-factors to enhance overall desulfurization rates as well as promoters to enhance enzyme expression. This research resulted in identification of NADH and FMNH2 as co-factors essential for electron transfer and related oxidoreductase enzymes as co-catalysts as described in detail below. Additionally, other bacterial strains were also investigated as hosts and are reported below. 

PEC. The patent includes the production method for the biocatalyst, with a characteristic inhibitory effect on certain enzyme expression. The expression recombinant vector contains a promoter free from manifesting inhibition due to an inorganic sulfur compound or a sulfur-containing amino acid. The recombinant microorganism also contains a gene for desulfurizing the sulfur-containing heterocyclic compound. 

Finally, a more MB-oriented patent concerns a gene which participates in desulfurizing enzyme expression inhibition [107], The production of the microorganism which highly expresses the desulfurizing enzyme, even when cultured in the presence of a sulfate as only one sulfur source was included. The application was focused towards the decomposition of thiophene compounds. 

Cali, J., Zwaagstra, J. C., Mons, N., Cooper, D. M. F. and Krupinski, J. Type VIII adenylyl cyclase-A Ca+2/calmodium-stimulated enzyme expressed in discrete regions of rat brain. /. Biol. Chem. 269 12190-12195,1994. 

CYP2C9 is the major CYP2C enzyme expressed in human liver [35] and plays a major role in the metabolism of numerous therapeutics including many weak acidic drugs such as the nonsteroidal anti-inflammatory compounds (e.g. flurbiprofen) [36] and antidiabetics (e.g. tolbutamide) [37]. In addition, CYP2C9 also metabolizes (S)-warfarin [38], lornoxicam [39] and phenytoin [37]. 

CYP3A is usually considered the most important of all drug-metabolizing enzymes as it accounts for nearly 40% of the total CYP enzymes expressed in the liver [15] and... 

Figure 2.12 Correlation plots of (A) transporter expression and (B) metabolic enzyme expression in duodenum between rat and human. The expression levels of transporters and metabolic enzymes are normalised by GADPH expression, transformed by natural logarithm and absolute values were used in the correlation analysis [121].

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