生物物理研究所成果被Nature China遴选为突出科研成果

2008年2月20日Nature China在研究亮点栏目发表评论，题目为：胰凝乳蛋白酶B，并非只是消化酶。评论了杨福愉课题组在胰凝乳蛋白酶B领域的最新工作。      

一直以来，胰凝乳蛋白酶B被认为是仅由胰脏分泌的消化酶。杨福愉组用多种层析方法从鼠肝溶酶体中纯化出了一种微量的蛋白酶，该蛋白酶分子量为25-kDa，在中性pH条件下具有极强的Bid剪切活性，可将Bid剪切为tBid，而生成的tBid可诱导线粒体快速释放细胞色素c。经长期探索并通过质谱分析及生化研究，该蛋白酶被鉴定为胰凝乳蛋白酶B (1)。

随后，他们进行了一系列实验验证其在肝脏溶酶体中的表达。蛋白质印迹分析及免疫荧光成像实验证明鼠肝溶酶体中确有胰凝乳蛋白酶B的表达。后续研究还发现，在细胞凋亡因素（如用TNF-a处理细胞）作用下，胰凝乳蛋白酶B可从溶酶体中释放到胞浆中。用BioPorter试剂将外源重组胰凝乳蛋白酶B转入细胞可诱导线粒体释放细胞色素c，并诱导细胞凋亡，提示胰凝乳蛋白酶B从溶酶体中释放后可通过线粒体途径引发细胞凋亡。进一步的实验表明，用胰凝乳蛋白酶B的抑制剂处理细胞，或用siRNA下调胰凝乳蛋白酶B的表达均可显著抑制TNF-a诱导的细胞凋亡。这些实验结果首次证明胰凝乳蛋白酶B不仅是一种仅由胰脏分泌的消化酶，更是一种可以在细胞凋亡过程中起重要作用的蛋白酶。

An achievements of Institute of Biophysics is selected as a prominent scientific research achievements by Nature China

On February 20, 2008, Nature China delivered a comment under the title: Chymotrypsin B is not only a digestive enzyme at Research Highlight. Nature China commented on Fuyu Yang Rsearch Team’s recent study in chymotrypsin B field.

We always consider that chymotrypsin B is a digestive enzyme which can only be secreted by pancreas. Fuyu Yang’s research team purified a trace amount of protease from lysosomes of rat liver by many kinds of chromatography methods.  The molecular weight of the protease is 25- kDa, with extremely high Bid cleavage activity under neutral pH.  It can cut Bid into tBid which in turn can induce in quick release of cytochrome c by mitochondria. Through a long-term endeavor and by virtue of mass spectrometry and biochemical study, the protease was identified as chymotrypsin B (1).

Afterwards, they conducted a series of experiments to test and verify its expression in lysosomes of liver. Western blotting analysis and immunofluorescence imaging experiment proved that chymotrypsin B is indeed expressed in lysosomes of rat liver. It was also found in follow-up studies that chymotrypsin B can be released to the cytoplasm from lysosomes under the action of apoptosis factors (for example, treating cells with TNF-a). Release of cytochrome c by mitochondria and apoptosis can be induced by using BioPorter reagent to carry over foreign recombinant chymotrypsin B into cells. It is shown from further experiments that apoptosis induced by TNF-a can be significantly inhibited by treating cells with inhibitors of chymotrypsin B or using siRNA to lower the expression of chymotrypsin B. These experiment results revealed that chymotrypsin B is not only a digestive enzyme secreted by pancreas but also a kind of protease which can play an important role in apoptosis for the first time.