title: The furofuran-ring selectivity, hydrogen peroxide-production and low Km value are the three elements for highly effective detoxification of aflatoxin oxidase.
abstract: AFO (aflatoxin oxidase), an enzyme from Armillariella tabescens previously named aflatoxin detoxifizyme, exhibits oxidative detoxification activity toward aflatoxin B1 and sterigmatocystin. Bioinformatics reveals that AFO is a newly discovered oxidase because AFO does not share any significant similarities with any known oxidase. It is critically important to understand how AFO acts on aflatoxin B1. In this study, in addition to aflatoxin B1 (AFB1) and sterigmatocystin (ST), five other chemicals that have furan or pyran structures were investigated. The results indicated that in addition to AFB1 and ST, AFO is also able to act on versicolorin A, 3,4-dihydro-2H-pyran and furan. These results suggested that 8,9-unsaturated carboncarbon bond of aflatoxin B1 is the potential reactive site for AFO. Further findings indicated that the action of AFO is oxygen-dependent and hydrogen peroxide-producing. The simultaneously produced-hydrogen peroxide possibly plays the essential role in detoxification of AFO. In addition, the extremely low Km value of 0.33 µmol/l for AFO-AFB1 and 0.11 µmol/l for AFO-ST signifies that AFO is highly selective for AFB1 as well as ST.
authors.affiliation: Department of Biotechnology, Jinan University, Guangzhou City 510632, Guangdong Province, China.
authors.forename: Yuan-Zhen
authors.initials: YZ
authors.lastname: Wu
authors.affiliation: Department of Biotechnology, Jinan University, Guangzhou City 510632, Guangdong Province, China.
authors.forename: Fu-Pu
authors.initials: FP
authors.lastname: Lu
authors.affiliation: Department of Biotechnology, Jinan University, Guangzhou City 510632, Guangdong Province, China.
authors.forename: Hai-Lan
authors.initials: HL
authors.lastname: Jiang
authors.affiliation: Department of Biotechnology, Jinan University, Guangzhou City 510632, Guangdong Province, China.
authors.forename: Cui-Ping
authors.initials: CP
authors.lastname: Tan
authors.affiliation: National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou City 510632, Guangdong Province, China.
authors.forename: Dong-Sheng
authors.initials: DS
authors.lastname: Yao
authors.affiliation: Department of Biotechnology, Jinan University, Guangzhou City 510632, Guangdong Province, China.
authors.forename: Chun-Fang
authors.initials: CF
authors.lastname: Xie
authors.affiliation: Department of Biotechnology, Jinan University, Guangzhou City 510632, Guangdong Province, China. Electronic address: tldl@jnu.edu.cn.
authors.forename: Da-Ling
authors.initials: DL
authors.lastname: Liu
mesh_terms: D016604:Aflatoxin B1 / Q000737:chemistry; D000880:Anthraquinones / Q000737:chemistry; D055392:Armillaria / Q000201:enzymology; D019295:Computational Biology; D005663:Furans / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D008658:Inactivation, Metabolic; D009097:Multienzyme Complexes / Q000737:chemistry*; D010843:Pichia / Q000378:metabolism; D013241:Sterigmatocystin / Q000737:chemistry
chemical_list: D000880:Anthraquinones; D005663:Furans; D009097:Multienzyme Complexes; C512150:aflatoxin-detoxifizyme, Armillariella tabescens; D013241:Sterigmatocystin; D016604:Aflatoxin B1; D006861:Hydrogen Peroxide; C029826:versicolorin A; C039281:furan
keywords: Aflatoxin enzymatic detoxification; Electrochemistry; Enzyme substrate selectivity; Oxidase