小麦根质膜原位膜微囊与翻转膜微囊的氧化还原特性比较

用二相法和不连续蔗糖梯度离心分别制得小麦根质膜的原位膜微囊和翻转膜微囊。两者比较可知：质膜内外两侧均表现出较高的氧化还原活性；膜内侧的ＮＡＤ（Ｐ）Ｈ氧化和Ｆｅ（ＣＮ）还原速率高于外侧。质膜内外两侧都能还原ＥＤＴＡ－Ｆｅ３＋，但外侧的还原活性高于内侧。质膜内外两侧均有Ｏ２吸收，同时都可被ＳＨＡＭ刺激，被ＫＣＮ抑制。质膜内侧和外侧都可产生，最适ＰＨ值为６．０；既可被ＳＨＡＭ刺激，也可被ＳＯＤ、过氧化氢酶和ＫＣＮ抑制。

Comparison of the Redox Properties of Right-side out and inside out Plasmalemma Vesicles Purified from Wheat Roots

Plasmalemma vesicles were purified from 8-day-old wheat(Triticum asetivum var. Longchun No. 10) roots bydiscontinuous sucrose gradient centrifugation (SG ) and aqueous two-phasepartitioning (PP ). The K , Mg2 ATPase activities of the plasmalemma vest.cles purified by SG and PP were inhibited 54 % and 60% respectively byvanadate. The inhibition of the ATPaseactivities of PP- and SG-purified plasmalemma by NaN3, NaNO3 andNaZMoO4 was 1 %, 1 %, and 2% and2 %, 2 %, and 4 %, respectively. ATPase latency measured with Triton X100 was 46% and 80% for SG-andPP-purified plasmalemma, respectively(Table 1 ). So the plasmalemma vesicles were mainly inside out (IO) forSG-purified vesicles and right-side out(RO) for PP-urifled vesicles.Both IO and RO had high redoxactivities. The rates of NAD(P)H oxidation and Fe (CN) reduction by IOwas higher than that by RO while theEDTA-Fe3 reduction of IO was lowerthan that of RO (Table 2). SHAM enhanced NADH oxidation (with O2 aselectron acceptor) and O2 uptake of IOand RO (Figs. 1, 2): SHAM-stimulatedNADH oxidation by IO was significanthigher than that by RO; But SHAMstimulated O2 uptake by IO was onlyslightly higher than that by RO. AndSHAM-stimulated NADH oxdation andO2 uptake by both tO and RO werecompletely inhibited by KCN.Both IO and RO generated O2 withan optimum PH value of 6. 0 (Fig. 3).The O2 production by IO and RO wasstimulated by SHAM and inhibited bySOD, catalase and KCN. However,Fe2 , Mn2 and IAA, 2, 4-D had noeffect on O2 generation by either IO orRO (Table 3). generation by ROwas enhanced by Ca2 -CaM but that byIO was not (Fig. 4 ). The redox properties of IO and RO were discussed in thepaper.