脓青素促进叶绿体中细胞色素b－559的光还原  

Pyocyanine Promoted the Photoreduction of Cytochrome b-559 in Chloroplasts

作　　者：王颖君[1] 叶济宇[1] 

机构地区：[1]中国科学院上海植物生理研究所

出　　处：《生物化学与生物物理学报》1996年第2期195-200,共6页

基　　金：国家自然科学重点基金;中国科学院上海植物生理研究所所长择优基金

摘　　要：当脓青素存在时，可以观察到菠菜叶绿体中光诱导的５５９ｎｍ吸收增加。此反应可以被光（波长６５０ｎｍ）诱导，但远红光（波长７２０ｎｍ）则无作用．光暗差示光谱表明被还原的物质为细胞色素ｂ－５５９。脓青素的作用在１μｍｏｌ／Ｌ接近饱和．并且其作用与跨膜质子梯度无关．脓青素所促进的细胞色素ｂ－５５９光还原被抑制剂ＤＣＭＵ和ＤＢＭＩＢ所抑制，但在氰化钾处理过的叶绿体中，脓青素依然促进细胞色素ｂ－５５９的光还原．在ＣＣＣＰ处理的叶绿体中，可以看到低光强红光诱导的细胞色素ｂ－５５９氧化。脓青素可以逆转ＣＣＣＰ的作用；促进细胞色素ｂ－５５９在高光强或低光强下都为红光还原。我们推测脓青素通过质子化作用，影响了细胞色素ｂ－５５９的光氧化还原反应．A light-induced absorbance increase at 559nm was observed in spinach chloroplasts in the presence of pyocyanine.The reaction was induced by red light (650nm) but not by far-red light (720nm ).The light-dark difference spectra indicated that the reduced component was cytochrome b-559. The effect of pyocyanine was nearly saturated at a concentration of 1 μM and was independent of the transmembrane proton gradient. The pyocyanine-promoted photoreduction of cytochrome b-559 was inhibited by inhibitors DCMU and DBMIB. In cyanidepoisoned chloroplasts pyocyanine still promoted the photoreduction of cytochrome b-559. In chloroplaste treated with CCCP the oxidation of cytochrome b-559 can be induced by red light of low intensity. Pyocyanine reversed the effects of CCCP so as to promote the reduction of cytochrome b-559 by red light of both high and low intensities. We assumed that pyocyanine affected the light-induced redoxreaction of cytochrome b-559 by affecting the protonation of the cytochrome.

关 键 词：叶绿体 细胞色素b-559 脓青素 光还原 

分 类 号：Q732[生物学—分子生物学]