CYP2E1 and metabolic dysfunction-associated steatohepatitis: Furthermore, in the NAFLD and NASH settings, ROS may also be formed in peroxisomes, where very-long-chain fatty acids initiate β-oxidation [53], and in the smooth endoplasmic reticulum, where ω-oxidation of fatty acids mediated by cytochrome P450 2E1 (CYP 2E1) takes place [54].