依次用三种溶液抽提处理菠菜光系统Ⅱ颗粒，离心后分别得到主要含１８ｋＤ，２４ｋＤ和３３ｋＤ水溶性蛋白的三种抽提液，利用ＳＤＳ聚丙烯酰胺凝胶电泳检测到前两种抽提液中均含蛋白酶．抽提液分别温育时，１８ｋＤ蛋白被降解而产生１７．１ｋＤ，１６ｋＤ，１４．４ｋＤ，１３．５ｋＤ和１２ｋＤ片段；２４ｋＤ蛋白被降解成２２ｋＤ，２０ｋＤ和１８ｋＤ．抑制剂实验表明，这２种抽提液中含有降解变性蛋白酶 Three spinach photosystem Ⅱ particles were extracted by three kinds of solutions in turn, and three kinds of extracts containing 18kD, 24kD and 33kD water-soluble proteins were obtained after centrifugation. The first two extracts were detected by SDS polyacrylamide gel electrophoresis Liquid containing protease. When the extracts were incubated separately, the 18 kD protein was degraded to produce 17.1 kD, 16 kD, 14.4 kD, 13.5 kD and 12 kD fragments; the 24 kD protein was degraded to 22 kD, 20 kD and 18 kD. Inhibitor experiments show that these two kinds of extracts contain degrading protease