Cytochrome P450 monooxygenase; part of the gene cluster that mediates the biosynthesis of oxaleimides, cytotoxic compounds containing an unusual disubstituted succinimide moiety. The first step of the pathway is provided by the HR-PKS poxF that serves in a new mode of collaborative biosynthesis with the PKS-NRPS poxE, by providing the olefin containing amino acid substrate via the synthesis of an ACP-bound dec-4-enoate. The cytochrome P450 monooxygenase poxM-catalyzed oxidation at the alpha-position creates the enzyme-bound 2-hydroxydec-4-enoyl-ACP thioester, which may be prone to spontaneous hydrolysis to yield 2-hydroxydec-4-enoic acid due to increased electrophilicity of the carbonyl. 2-hydroxydec-4-enoic acid can then be further oxidized by poxM to yield the alpha-ketoacid 2-oxodec-4-enoicacid, which is reductively aminated by the aminotransferase poxL to yield (S,E)-2-aminodec-4-enoic acid. The Hybrid PKS-NRPS synthetase poxE then performs condensation between the octaketide product of its PKS modules and the amino group of (S,E)-2-aminodec-4-enoic acid which is activated and incorporated by the adenylation domain. The resulting aminoacyl product can be cyclized by the Diels-Alderase PoxQ and reductively released by the reductive (R) domain of poxE to yield an aldehyde intermediate (Probable). The released aldehyde is then substrate for a Knoevenagel condensation by the hydrolyase poxO followed by an oxidation at the 5-position of the pyrrolidone ring. The presence of the olefin from the amino acid building block allows for migration of the substituted allyl group to occur. This allylic transposition reaction takes place in a conjugate addition, semipinacol-like fashion to yield a succinimide intermediate. Iterative two-electron oxidations of the C7 methyl of the succinimide intermediate to the carboxylic acid can be catalyzed by one of two remaining cytochrome P450 monooxygenasess poxC or poxD to yield oxaleimide A. Subsequent oxidation yields the maleimide scaffold oxaleimide I. Both oxaleimide A and oxaleimide I can undergo oxidative modifications in the decalin ring to yield the series of products oxaleimides B to H