Microbial Oxidation of KE-298 Metabolites by Rhizopus sp. and Rhodococcus sp. Strains

Area of Science:

• Biochemistry
• Microbiology
• Drug Metabolism

Background:

• The antirheumatic agent KE-298 undergoes metabolism in humans, producing several key metabolites.
• Understanding these metabolic pathways is crucial for drug efficacy and safety.

Purpose of the Study:

• To synthesize and identify the human metabolites of the antirheumatic agent KE-298.
• To elucidate the microbial transformation pathways involved in metabolite production.
• To investigate the enzymatic mechanisms, particularly the role of cytochrome P-450, in these biotransformations.

Main Methods:

• Microbial transformation of the substrate KE-748 using Rhizopus sp. TF0040 to produce (-)-(2R)-M-4.
• Co-oxidation of (-)-(2R)-M-4 using Rhodococcus sp. TA0250 to produce (-)-(2R)-M-6.
• Chemical synthesis of (-)-(2R)-M-5 and (-)-(2R)-M-7 from (-)-(2R)-M-4 and (-)-(2R)-M-6, respectively, using m-chloroperoxybenzoic acid.
• Inhibition studies using cytochrome P-450 inhibitors (SKF-525-A and metyrapone) to determine enzyme involvement.

Main Results:

• (-)-(2R)-M-4 was synthesized from KE-748 via microbial transformation with Rhizopus sp. TF0040.
• (-)-(2R)-M-6 was produced from (-)-(2R)-M-4 through co-oxidation by Rhodococcus sp. TA0250.
• Cytochrome P-450 inhibitors significantly inhibited the hydroxylation reaction, suggesting its involvement in the microbial process.
• The synthesis of diastereomers (-)-(2R)-M-5 and (-)-(2R)-M-7 was achieved through chemical oxidation.

Conclusions:

• Microbial transformation is an effective method for synthesizing key human metabolites of KE-298.
• Cytochrome P-450 enzymes play a significant role in the microbial hydroxylation of KE-298.
• The study provides insights into the metabolic fate of KE-298 and the enzymes involved.