VKORC1L1 (vitamin K epoxide reductase complex subunit 1-like 1) is a membrane-bound enzyme located in the endoplasmic reticulum that plays crucial roles in vitamin K metabolism and cellular antioxidant defense 1. The enzyme catalyzes the reduction of vitamin K 2,3-epoxide to active vitamin K, supporting vitamin K-dependent gamma-carboxylation of glutamic acid residues in target proteins 2. VKORC1L1 demonstrates distinct kinetic properties from its paralog VKORC1, with different sensitivities to oral anticoagulants like warfarin due to different binding sites 3. Beyond its role in vitamin K metabolism, VKORC1L1 serves as a critical antioxidant enzyme that protects cells from oxidative stress and ferroptosis by maintaining intracellular redox homeostasis 14. The enzyme's expression is upregulated under oxidative stress conditions, and its activity is essential for vitamin K-mediated protection against reactive oxygen species 1. Clinically, VKORC1L1 polymorphisms influence warfarin dosing requirements 5, and the enzyme has emerged as a potential therapeutic target in cancer, where its inhibition by warfarin may sensitize tumors to ferroptosis-inducing therapies 67.