高纯度烟草过氧化物酶（TOP I）光谱特性研究

采用交换吸附脱色及柱层析新技术，成功地从烟叶中分离和纯化了一种烟草过氧化物酶同工酶(TOP I)，并对其进行了一系列光谱特性研究。基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)测得TOP I分子量为21888．5，等电点pI为3．5；氨基酸组成分析表明TOP I为一含血红素的酸性蛋白酶。光谱学分析揭示，在402nm处有一典型的Soret带，在498和636nm处有特征吸收峰(α，β带)，酸度和变性剂对TOP I在紫外可见区的特征吸收峰均产生一定的影响，TOP I的荧光光谱测定结果说明TOP I分子中含有Trp残基和Tyr残基以及其自身的独特的光谱学特性。

Study on the Spectral Characteristics of Tobacco Peroxidase I with High Purity

Tobacco peroxidase (TOPI) has been purified by ammonium sulfate fractionation and column chromatography, involving ion exchange on DE-52 cellulose, gelfiltration on Sephadex G-75 and ion exchange on DEAE-sephadex A-50. The specific activity of peroxidase purified was 4,826 U/mg. It has been demonstrated by SDS-PAGE as a single band. Its molecular weight (matrix assisted laser desorption/ionization time of flight mass spectra) and isoelectric point (pI) have been determined to be 21,888.5 and 3.5 respectively. The native enzyme is one of a haemachrome-containing acidic protein and has its soret maximum at 402 nm and alpha and beta bands at 636 nm and 498 nm, respectively. Its characteristic absorption spectra and fluorescence spectra changed in different pH and denaturant. It has its own characteristic absorption spectra and fluorescence spectra.