ARS | Publication request: HypC is the anthrone oxidase involved in aflatoxin biosynthesis

Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 18, 2010
Publication Date: March 26, 2010
Citation: Ehrlich, K., Li, P., Scharfenstein, L.L., Chang, P. 2010. HypC, is the anthrone oxidase involved in aflatoxin biosynthesis. Applied and Environmental Microbiology. 76(10):3374-3377.

Interpretive Summary: Several important U.S. crops, for example, corn, cotton, peanuts, are often contaminated by Aspergillus species that make the toxic and cancer-causing chemical, aflatoxin. How the fungus makes this chemical has been the subject of intensive study by the Food and Feed Safety group at SRRC. Now, with the complete Aspergillus flavus sequence available, most of the genes involved in the production of this chemical are known. However, one of these genes, hypC, was listed as “hypothetical,” hence the designation “hyp.” The studies reported in this paper prove that this gene makes an enzyme that is involved in the first of more than twenty-five steps that allows the precursor chemical, called a polyketide, to be oxidized to aflatoxin. Since this enzyme is only made by fungi it could be a plausible target for inhibitory chemicals that would prevent aflatoxin formation.

Technical Abstract: Based on gene disruption and enzyme activity, hypC, an open reading frame in the pksA (aflC)/nor-1 (aflD) intergenic region in the aflatoxin biosynthesis cluster, encodes a 17 kDa oxidase that catalyzes the conversion of norsolorinic acid anthrone to norsolorinic acid.