Campaign C · The Atypical Hub

Not every P450 is a classic monooxygenase

The Special tier captures atypical P450 mechanisms—hydroperoxide lyase chemistry without NADPH/O₂ dependence. These routes are tagged ΔMass: Exempt via chemical-intuition routing so cleavage reactions are not falsely rejected.

6Special reactions
6ΔMass exempt
6CYP74 family
Flagship case study

CYP749B1 · CYP749B

Withania somnifera

12-deoxywithastramonolide ➜ withanolide A
Mechanism
Atypical_Cleavage — hydroperoxide lyase → short-chain GLV mixture
ΔMass
Exempt (atypical cleavage; mass rules do not apply)
Literature
PMID:35102209
ation; ation; Overexpression of WsCYP749B1 increased withanolide A (>250%) and decreased 12-deoxywithastramonolide (~60%), suggesting conversion.
View full reaction card →

CYP74 atypical cleavage zone

HPL / CYP74: long-chain fatty-acid hydroperoxides → green leaf volatiles (GLVs); chain cleavage breaks ΔMass alignment.

Special Atypical cleavage ΔMass Exempt
CYP74B2 Oryza sativa

hydroperoxylinolenic acid → green leaf volatiles

PMID 39769161
Special Atypical cleavage ΔMass Exempt
CYP74 Linum usitatissimum

13(S)-hydroperoxylinolenic acid → allene oxide

PMID 8378325
Special Atypical cleavage ΔMass Exempt
CYP749B1 Withania somnifera

12-deoxywithastramonolide → withanolide A

PMID 35102209
Special Atypical cleavage ΔMass Exempt
CYP749B1 Withania somnifera

withanolide A → withanolide B

PMID 35102209
Special Atypical cleavage ΔMass Exempt
CYP749B1 Withania somnifera

cycloartenol → sitosterol

PMID 39124289
Special Atypical cleavage ΔMass Exempt
CYP74A2 Parthenium argentatum

13(S)-hydroperoxy-9(Z),11(E)-octadecadienoic acid → allene oxide

PMID 18787124

Full Special mechanism library

Browse in reaction grid →
EnzymeSpeciesReactionΔMassPMID
CYP74B2 Oryza sativa hydroperoxylinolenic acid → green leaf volatiles Exempt 39769161
CYP74 Linum usitatissimum 13(S)-hydroperoxylinolenic … → allene oxide Exempt 8378325
CYP749B1 Withania somnifera 12-deoxywithastramonolide → withanolide A Exempt 35102209
CYP749B1 Withania somnifera withanolide A → withanolide B Exempt 35102209
CYP749B1 Withania somnifera cycloartenol → sitosterol Exempt 39124289
CYP74A2 Parthenium argentatum 13(S)-hydroperoxy-9(Z),11(E… → allene oxide Exempt 18787124