摘要
番茄系统感染ＴＭＶ（ｔｏｂａｃｃｏ ｍ ｏｓａｉｃｖｉｒｕｓ）诱导叶β－Ｎ－乙酰氨基己糖苷酶活性升高。番茄叶胞外提取液经冰冻干燥浓缩、－ ２０℃丙酮沉淀、ＣＭ－Ｓｅｐｈａｄｅｘ Ｃ－２５ 离子交换层析，ＰＢＥ ９４（Ｐｏｌｙｂｕｆｆｅｒ Ｅｘｃｈａｎｇｅｒ ９４， Ｓｉｇｍ ａ）聚焦层析和Ｓｅｐｈａｄｅｘ Ｇ－１５０ 凝胶层析纯化，获得纯化的β－Ｎ－乙酰氨基己糖苷酶。凝胶层析测得该酶的分子量为１４５ ｋＤ，ＳＤＳ－ＰＡＧＥ测得该酶的分子量为７５ ｋＤ，证明该酶由两个亚基构成。该酶能水解ｐ－硝基苯基－Ｎ－乙酰－β－Ｄ－氨基葡萄糖苷（ｐＮＰ－β－Ｄ－ＧｌｃＮＡｃ）和Ｐ－硝基苯基－Ｎ－乙酰－β－Ｄ－氨基半乳糖苷（ｐＮＰ－β－Ｄ－ＧａｌＮＡｃ）两种底物，能被过碘酸氧化，Ｓｃｈｉｆｆ试剂染色。在感染ＴＭＶ 的番茄叶片中。
Systematic infection of tomato (Lycopersicon esculentum) leaves by tobacco mosaic virus (TMV) increased the levels of β N acetyl D hexosaminidase activity.The enzyme was purified from intercellular fluid by -20℃ acetone precipitation, CM Sephadex C 25 ion exchange chromatography, Polybuffer Exchanger 94 chromatofocusing and Sephadex G 150 gel filtration column to homogeneity.The molecular weight obtained by SDS PAGE and Sephadex G 150 gel filtration was 75 kD and 145 kD respectively.The enzyme hydrolysed p nitrophenyl N acetyl β glucosaminide and p nitrophenyl N acetyl β galactosaminide, it was a glycoprotein.Most of the enzyme activity in the TMV infected tomato leaves was found in the intercellular spaces.
