Deoxypatulinic acid

Scheme 1 also includes deoxypatulinic acid (37) (Scheme 1), which has been shown to be a cometabolite of patulin in P. patulum (Scott et al., 1972). The questions that arise are the following Is it an end product of patulin (1) metabolism Is it an end product of gentisaldehyde (9) metabolism Or is it an intermediate between gentisaldehyde (9) and patulin (1) These three biogenetic mechanisms are described in Fig. 25. Scheme a represents the metabolism of patulin (reduction). Scheme b would involve extensive reduction of the cleavage product of gentisaldehyde followed by dehydration and isomerization. Deoxypatulinic acid (37) either could be an end product or could be converted to patulin as outlined in scheme c. 

Most of the steps in Scheme 1 have been established at the enzymatic level (heavy arrows the enzymes detected are shown above these arrows). The unanswered questions in the biosynthesis of patulin are the following (a) What is the absolute configuration of the optically active deuteropatulin generated from the feeding of ring-deuterated aromatic precursors (b) Is deoxypatulinic acid (37) in Scheme 1 involved in patulin biosynthesis or in its metabolism (c) Is patulin-lactone (35) a metabolite of P. patuluml If not, why are the side-chain deuteriums lost in the conversion of the aromatic precursors into patulin ... 

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