Drug metabolizing enzymes (DMEs) play a role in modifying drug activity and in modulating the clearance of target compounds such as endo- and xenobiotics, small molecule drugs, steroid hormones and dietary flavonoids. Thus, the evaluation of metabolites generated by DMEs is required for drug development, food science and environmental assessment. Here, we generated a library of DMEs expressed in yeast cells as a means of studying xenobiotic metabolism from early phase metabolic screening to structural determination and evaluation. In this review, advantages of the DME expression system are introduced as well as applications of the DME platform for studying drug metabolism.

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Alginate-degrading bacteria were isolated from seawater and a-systematic classification was performed using 16S rDNA sequence. The isolated strain was identified as Microbulbifer sp. strain KIT-19. The properties of alginate lyase (ALG19) derived from the strain KIT-19 were investigated. ALG19 was purified by various column chromatography techniques, with specific activity of 10.1 units/mg and 7.08-fold purity. When the substrate was sodium alginate, the optimum pH of the purified ALG19 was 8.5 and optimum temperature was 40°C. The activity of the purified ALG19 increased by 2.34-fold in the presence of 100 mM Na+ . Alginate is composed of β-D-mannuronic acid (M) and 1,4-linked α-L-guluronic acid (G) residues. The activity toward poly- M blocks and poly-G blocks of purified ALG19 on the basis of relative activity scale were 123% and 91% respectively, when the decomposed activity to sodium alginate was 100%. Since ALG19 was poly-M blocks specific alginate lyase, it was thought that ALG19 belongs to the polysaccharide lyase (PL)-7 family. ALG19 could be considered to be an endo-type enzyme because it lowers the kinematic viscosity of sodium alginate from 23.5 to 1.65 cSt (mm2 /s).

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As the currently available therapies for HIV-1 have high costs and are associated with the appearance of multi-drug resistant HIV-1 strains, the Indian traditional medicine system Ayurveda may provide useful alternatives. In this study, we screened the inhibitory activities of various extracts of five Indian plants for inhibitory effects on HIV-1 reverse transcriptase (RT). Water extracts of the leaves of Argemone mexicana strongly inhibited the DNA polymerase activity of HIV1 RT, which indicated that they contained substances with inhibitor activity. Neither heat treatment at 100ºC nor proteinase K treatment of the extracts abolished the inhibitory activity, suggesting that the inhibitory substance was an organic compound rather than a protein.

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