Aspergillus niger Epoxide Hydrolase as an alternative model to study human cholesterol epoxide hydrolase

BISOGNO F.R; ORDEN A.A.; GIORDANO O.S; KURINA SANZ M.

Merlo, San Luis, Argentina

Congreso; XXII Reunión Científica Anual de la Sociedad Biológica de Cuyo; 2004

Sociedad de Biología de Cuyo

Colestan-5-epoxi-3b-ol and its metabolite colestan-3b,5a,6b-triol are not only involved in aterogenesis processes but also in mutagenic and citotoxic activities. A. niger epoxide hydrolase shows structural and mechanistic analogies with human microsomal epoxide hydrolase. A fungal model using whole cell cultures of A. niger ATCC 11394 has been developed in order to mimic human metabolism. A two- step assay using batch culture system was performed. Firstly, ten 125ml batch containing 30ml of Czapeck medium, were inoculated with A.niger spores and submitted to rotatory agitation (180 rpm) for 24hs at 28°C. Then pellets were transferred to ten batchs with fresh medium and cultured at the same conditions for 24hs. The substrate, 10 mg of colestan-5-epoxi-3b-ol, was dissolved in 20ml of EtOH and added to each batch. After a 14 days incubation the bioconversion products were checked by TLC, purified and characterized by 1H ,13C NMR and MS techniques. This model results in a cheaper, simpler, easier-to-handle and less risky alternative system than the use of mammalian tissue cultures.