Human vitamin K 2,3-epoxide reductase complex subunit 1-like 1 (VKORC1L1) mediates vitamin K-dependent intracellular antioxidant function.

ABSTRACT: Human vitamin K 2,3-epoxide reductase complex subunit 1-like 1 (VKORC1L1), expressed in HEK 293T cells and localized exclusively to membranes of the endoplasmic reticulum, was found to support both vitamin K 2,3-epoxide reductase (VKOR) and vitamin K reductase enzymatic activities. Michaelis-Menten kinetic parameters for dithiothreitol-driven VKOR activity were: K(m) (μM) = 4.15 (vitamin K(1) epoxide) and 11.24 (vitamin K(2) epoxide); V(max) (nmol·mg(-1)·hr(-1)) = 2.57 (vitamin K(1) epoxide) and 13.46 (vitamin K(2) epoxide). Oxidative stress induced by H(2)O(2) applied to cultured cells up-regulated VKORC1L1 expression and VKOR activity. Cell viability under conditions of no induced oxidative stress was increased by the presence of vitamins K(1) and K(2) but not ubinquinone-10 and was spec

SUBMITTER: Westhofen P 

PROVIDER: S-EPMC3083210 | biostudies-literature | 2011 Apr

REPOSITORIES: biostudies-literature