无机盐对葡萄叶CPOD活性的影响

研究了盐渍下华北葡萄叶过氧化物酶活性变化。分离纯化了一种带正电荷的过氧化物酶（ＣＰＯＤ）并研究了其部分特性。结果表明，在ＮａＣｌ 浓度大于１００ ｍ ｍｏｌ／Ｌ时，叶片过氧化物酶总活性下降，但ＮａＣｌ 浓度为１５０ ｍ ｍｏｌ／Ｌ时ＣＰＯＤ仍不受影响。该ＣＰＯＤ可用ＤＥＡＥ－ 纤维素柱和人造沸石柱纯化，其最适ｐＨ 为６．１４～６．４７，对蛋白的表观Ｖｍ ａｘ 为４ ０８２ Ｕ／ｍｇ，对Ｈ２ Ｏ２ 的表观Ｋｍ 为３．４９ ｍ ｍｏｌ／Ｌ。高浓度无机盐刺激纯ＣＰＯＤ 活性增加，推测该ＣＰＯＤ 可能在葡萄抗盐中有重要作用。

Influence of Salt on the Activity of a Cationic Peroxidase in Leaves of Vitis bryonifolia

Changes in activity of peroxidase in leaf disks of Vitis bryonifolia under salinity were investigated. A cationic peroxidase was purified, its properties were partially characterized.The results showed that the activity of total peroxidase was decreased by NaCl of concentrations above 100 mmol/L, but the activity of cationic peroxidase was not influenced by treatment of 150 mmol/L NaCl.The cationic peroxidase could be purified with DEAE-cellulose column and synthesized zeolite column. The purified cationic peroxidase had an optimum catalytic pH value from 6.14 to 6.47, an apparent Vmax(protein)of 4 082 U/mg, and an apparent Km(H2O2) of 3.49 mmol/L,when guaiacol was used as substrate.The cationic peroxidase was stimulated by high concentrations of inorganic salts. We concluded that the cationic peroxidase might play an important role in adapting response of Vitis to salinity.