Broad substrate Cytochrome P450 monooxygenase activity in the cells of Aspergillus terreus MTCC 6324

Abstract

Cytochrome P450 (CYP) monooxygenase activities with different category of substrates namely, alkanes, alkane derivatives, alcohols, aromatic compounds, organic solvents, and steroids were detected in the cells of Aspergillus terreus. High CYP specific activity was observed when methanol (5.6 ± 0.017 U mg −1), acetone (7.76 ± 0.02 U mg −1), dimethylsulphoxide (DMSO) (9.70 ± 0.005 U mg −1), n-hexadecane (4.39 ± 0.02 U mg −1), or n-octadecane (4.23 ± 0.01 U mg −1) were used as substrates. Significant CYP specific activity was also detected when naphthalene (3.80 ± 0.002 U mg −1) was used as substrate. The CYP catalysis of n-hexadecane had followed both terminal and sub terminal oxidations. The activity was localized in the cytosol of n-hexadecane grown cells, while, it was apparently distributed in light mitochondrial fraction and microsomal fraction of glucose grown cells. The substrate specificities of CYP present in all the locations were similar irrespective of the substrates used for the growth. Heme staining of the microsomal fraction containing CYP and other proteins in SDS–PAGE showed single heme protein band with corresponding molecular weight of 110 kDa.