MEOS oxidizes ethanol to acetaldehyde

The MEOS (microsomal ethanol oxidizing system) is an accessory pathway in the liver which increases in activity on chronic alcohol induction. The MEOS utilizes a cytochrome P450 which has since been deciphered to be CYP2E1, an ethanol-inducible form of P450. CYP2E1 also increases acetaldehyde formation and free radicals which can initiate lipid peroxidation. CYP2E1 can also activate many over-the-counter medicines and solvents to toxic metabolites and deplete retinoids resulting in their depletion and deletrious effects. This is because, being a cytochrome P450 and using NADPH and oxygen, it has the ability to biotransform drugs when it has been induced by ethanol.

MEOS（微粒体乙醇氧化系统）是肝脏中的一个辅助途径，其活性在慢性酒精诱导下会增强。MEOS利用一种细胞色素P450，该酶已被解析为CYP2E1，一种由乙醇诱导的P450形式。CYP2E1还能增加乙醛和自由基的形成，从而启动脂质过氧化。此外，CYP2E1还能激活许多非处方药物和溶剂，使其转化为有毒代谢物，并耗竭视黄醇，导致其耗竭及产生有害影响。这是因为作为一种细胞色素P450，它利用NADPH和氧气，在乙醇诱导下具有生物转化药物的能力。（cytochrome P450）