The expression quantity increased with the induction time by iptg , and accounted for 25 percent of the total proteins after 4 - hour induction . absorption spectrum together with xanthophyll pigments quantification by hplc demonstrated that the expressed vde has its enzyme activity , which can de - epoxidate v into a and z in vitro 吸收光譜差值a _ ( 502 - 540 )隨反應(yīng)的進(jìn)行逐漸增大,反應(yīng)體系總色素的hplc分析表明, v逐漸降低,而z剛好相反,說(shuō)明表達(dá)的蛋白具有與活體vde酶相同的功能,能在體外將v轉(zhuǎn)變?yōu)閍和z 。