地钱、肾蕨和中山柏中的NADP硫氧还蛋白系统

NADP/Thioredoxin System in Marchantia polymorpha, Nephrolepis cordifolia and cupressus lusitanica

硫氧还蛋白(Td)是一类低分子量酸性蛋白,具有二硫键(-s-s-),通过氧化还原互变来参与很多反应(周志民等1986)。Td可被NADP-硫氧还蛋白还原酶(NTR)还原:

NADP / thioredoxin system is comopsed ofNADP, thioredoxin and NADP-thioredoxinreductase. NADPH is used as a hydrogen donorfor the reduction of thioredoxin. Such systemis found in bacteria, fungi, animal cells as wellas in plant seeds and cultured cells. We intendto know if this system exists in green plant cellsAnd if it remains in plant phylogenesis and inlife evolution. Nephrolepis cordifolia leaves, light grown Mar-chantia polymorpha and Cupressus lusitanica cv.Zhongshan cultured cells were used as the repre-sentatives of different positions in plant phyloge-nesis. The cell-free extracts of the three mate-rials were applied to DEAE-cellulose (DE-52)columns (2.6×15.5 cm). NADP-dependentmalate dehydrogenase activation assay was usedfor the detection of thioredoxin, the DTNB reduc-tion assay was used for the detection of NADP-thioredoxin reductase. The elution profiles of the three materialsshowed thioredoxin and NADP-thioredoxin re-ductase activities, which indicated that NADP/thioredoxin system existed in the materials.The NADP-thioredoxin reductase activitiesof light and dark grown C lusitanica cv. Zhong-shan cultured cells were compared. Based on theequal protein content of samples, the ratio was1/8 for light / dark. It is concluded that NADP / thioredoxin sys-tem is important during plant evolution, itexists not only in bacteria, fungi and animal cells,but also in green plant cells. It is evident thatthis system is predominant in dark grown cul-tured cells. Maybe the different content of reduc-tase can casue the difference of enzyme activity.