质膜氧化还原系统中的抑制物及其特性

燕麦（Ａｖｅｎａ ｓａｔｉｖａ）质膜氧化还原系统的酶反应进行一段时间后，酶反应速率逐渐降低到零，加入反应底物ＮＡＤＨ、Ｋ３Ｆｅ（ＣＮ）６ 以及质膜（酶）不能使酶反应速率得到恢复，说明酶被抑制． 酶反应的产物可能为ＮＡＤ＋ 、Ｆｅ２＋ 和Ｈ＋ ，加入ＮＡＤ＋ 、Ｋ４Ｆｅ（ＣＮ）６ 和ＨＣｌ不能使酶活力抑制，因此不是产物反馈抑制． 超速离心除去质膜后，发现抑制物存在于反应介质中，这种抑制物的抑制效果随时间延长而降低，所以此抑制物不稳定． 本文首次报道质膜氧化还原系统中存在抑制物

INHIBITOR OF REDOX SYSTEM IN PLANT PLASMALEMMA AND ITS PROPERTIES

NADH K 3Fe(CN) 6 (FeCN) reductase activity was decreased to zero after 10 min or more of reaction. The activity was not recovered by the addition of substrates, NADH and FeCN, and plasmalemma together or separately. The probable reaction products, NAD , Fe 2 and H , were proved not to be as feed back inhibitors. The reaction medium containing plasmalemma, NADH and FeCN was centrifuged after incubation. It was found that the inhibitor was in the supernatant and the inhibitivity was lost after some six hous of storage.