title: Biosynthetic origin of aflatoxin G1: confirmation of sterigmatocystin and lack of confirmation of aflatoxin B1 as precursors.
abstract: The origin of aflatoxin G1 was studied using mutant strains of Aspergillus parasiticus blocked early in the pathway and by tracing 14C-labelled aflatoxin B1 (AFB1) in wild-type A. flavus and A. parasiticus strains. Sterigmatocystin (ST) was a precursor of AFB1, AFG1 and AFG2 in the four mutants examined. The identity of AFG1 was confirmed by mass spectrometry. No evidence for conversion of AFB1 to AFG1 was found. A rigorously controlled study of conversions of radioactivity based on preparative thin-layer chromatography of aflatoxins demonstrated that low levels of aflatoxin interconversions previously reported in the literature might actually be artifacts.
mesh_terms: D016604:Aflatoxin B1; D000348:Aflatoxins / Q000096:biosynthesis* / Q000378:metabolism*; D001230:Aspergillus / Q000378:metabolism; D001711:Biotransformation; D002855:Chromatography, Thin Layer; D013241:Sterigmatocystin / Q000493:pharmacokinetics*; D014966:Xanthenes / Q000493:pharmacokinetics*
chemical_list: D000348:Aflatoxins; D014966:Xanthenes; D013241:Sterigmatocystin; C027955:aflatoxin G1; C029754:aflatoxin G2; C029753:aflatoxin B2; D016604:Aflatoxin B1