超声波对菠萝果蛋白酶活性和光谱的影响

Effect of ultrasound on the activity and spectrum of fruit bromelain

以菠萝果为材料,用盐析法制备菠萝果蛋白酶粗酶,进一步经Sephadex G-50和DEAE-纤维素柱层析纯化,其SDS·PAGE呈单一的电泳带,并获得了菠萝果蛋白酶结晶。一定参数的超声作用可以使酶活力提高,经光谱分析,超声处理后酶的吸收光谱不改变,而荧光发射峰由336nm红移到339nm,紫外差示光谱在一定的波长也呈现出明显的正峰和负峰。本文讨论了超声波影响菠萝果蛋白酶活性的机理。

Crude fruit bromelain was prepared from fruit juice of pineapples by means of salting out with (NH4)SO4. It was further purified by chromatography on gel filtration on Sephadex G-50 and DEAE-cellulose. The preparation was shown to exhibited a single band on SDS-PAGE and was crystallized on 4℃ after keeping at low temperature for a period of time. The activity of fruit bromelain was increased when it was treated by sufficient ultrasound. The spectrum analysis showed that the fluorescence emission peak of the enzyme affected by ultrasound was red-shifted from 336nm to 339nm. Differential UV-spectra also presented distinct negative peaks and positive peaks. The action mechanism of the effect of ultrasound on fruit bromelain activity was discussed.