FIGURE 2.

VKOR activation by Trx and TrxR. Solubilized (a) or unsolubilized (b) microsomes prepared from insect cells infected with baculovirus containing wild type VKOR were incubated in a vitamin K epoxide reduction reaction containing buffer A, vitamin K epoxide, and either DTT or E. coli Trx, TrxR, and NADPH. After 30 min of incubation, the vitamin K forms were isolated by organic extraction and quantitated by absorbance using HPLC. The range in values that were obtained is indicated by the error bars, which in the case of the Trx/TrxR assay in b is too small to be observable.