【摘要】 以盐生的大米草（Ｓｐａｒｔｉｎａａｎｇｌｉｃａ）为实验材料，ＢＢＹ法制备ＰＳⅡ颗粒，氧电极法测定其放氧活性，并通过ＳＤＳ－ＰＡＧＥ及盐洗等手段对其多肽组分及特性进行了探索．结果显示①大米草尽管生长在盐生的环境中，但其ＰＳⅡ放氧活性（９９．９２μｍｏｌＯ２／ｍｇＣｈｌ·ｈ）和菠菜接近，但比分类地位较接近的小麦要高出１倍．②外加ＣａＣｌ２后，大米草ＰＳⅡ放氧活性由原来的９９．９２μｍｏｌＯ２／ｍｇＣｈｌ·ｈ增加到１１４．２０μｍｏｌＯ２／ｍｇＣｈｌ·ｈ，表明Ｃａ２＋的数量和分布与放氧过程密切相关．③多肽组分分析表明，大米草ＰＳⅡ由１３条多肽组成，比中生类型的植物增加了分子量为６７０００和５００００的２两条多肽．④盐洗后，放氧活性降低，回加ＣａＣｌ２，放氧活性得到一定程度的恢复．多肽组分分析显示盐洗后，分子量为２４０００，１８０００及其它４条小分子多肽有不同程度丧失．这表明盐生大米草与放氧有联系的多肽和菠菜、小麦存在差异更多还原

【Abstract】 The photosystem Ⅱ(PSⅡ) complex is a complicated membrane protein and is located in the appressed region of the thylakoid membrane.Oxygen-evolving PSⅡ particles have been isolated from halophyte Spartina anglica in this paper,and the measurement of O 2-evolution activity demonstrated the PSⅡ particles had a great of O 2-evolving.SDS-PAGE profile indicated that the PSⅡ particles contained 13 polypeptides,hence the composition of PSⅡ polypeptides was different from mesophyte(spinach,wheat). A treatment of the PSⅡ particles with 2.0 M NaCl showed the 24000 and 18000 polypeptides could be released from the PSⅡ particles of Spartina anglica.Meanwhile,the 34000,27000,25000, 22000 were also released partly.By addition of 5mmol/L Ca 2+ the O 2-evolution activity could be partly restored and the Ca 2+ in PSⅡ particles is essential to O 2-evolving.更多还原