【摘要】 烟草过氧化物酶同工酶Ⅰ (TOPⅠ )的分离纯化过程 ,主要包括匀浆、超声破碎、过滤、(NH4) 2 SO4分级沉淀、DE 5 2纤维素阴离子交换层析、SephadexG 75凝胶层析、DEAE SephadexA 5 0阴离子交换层析 .经纯化的TOPⅠ ,纯化酶的比活力为 482 6U/mg ,在SDS PAGE上显示出一条蛋白带 ,分子量在 2 1 0 0 0左右 ,基质辅助激光解吸电离飞行时间质谱 (MALDI$CTOF MS)测得TOPⅠ分子量为 2 1 888.5 ,等电点pI为 3.5 ;光谱学分析揭示 ,在 40 2nm处有一典型的Soret带 ,在 498nm和 636nm处有特征吸收峰 ,表明TOPⅠ为一含血红素的酸性蛋白酶 .酸度对TOPI的在紫外可见区的特征吸收峰及荧光光谱均产生一定的影响 ,反映了TOPⅠ分子独特的光谱学特性更多还原

【Abstract】 Tobacco peroxidase I has been purified by ammoniu m sulfate fractionation and column chromatography, involving ion exchange on DE-5 2 cellulose, gel filtration on Sephadex G-75 and ion exchange on DEAE-Sephadex A-50. The specific activity of peroxidase purified is 4 826 U/mg. It has been demonstrated by SDS-PAGE as a single band, and its molecular weight and isoelec tric point have been determineted as 21 888.5 and 3.5 respectively. The native e nzyme is one of a haemachrome-containing acidic protein. Electronic absorption spectrum of native tobacco Peroxidase I shows that its maximum Soret peak, α an d β bands was at 402nm, 636nm and 498nm respectively. Its characteristic absor ption spectra and fluorescence spectra have been changed in different pH. The re sult of the spectrums mentioned exhibits its characteristic spectroscopy propert y.更多还原