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用离体细胞壁伸展活性重组法，对大豆（Ｇｌｙｃｉｎｅｍａｘ（Ｌ．）Ｍｅｒ．）幼苗下胚轴细胞壁特异性扩张蛋白的活性鉴定和特性研究结果表明，大豆幼苗下胚轴的延伸生长，既与扩张蛋白的活性升高有关，也与其细胞壁对扩张蛋白的敏感性增加有关；热钝化大豆下胚轴细胞壁的伸展活性，一旦被外源扩张蛋白所恢复，用酸性缓冲液（ｐＨ４．５）代替扩张蛋白提取液，伸展活性不受影响；但若换用中性缓冲液（ｐＨ６．８），伸展活性丧失殆尽，且与活细胞壁一样，随缓冲液的交替更换而反复逆转；大豆和黄瓜幼苗扩张蛋白可以与其热钝化的细胞壁相互交叉重组。另外，重组的细胞壁伸展活性对扩张蛋白浓度和ｐＨ的依赖性，符合一般酶的催化特征，说明扩张蛋白不仅在植物细胞的延伸生长过程中起着极为重要的作用，而且还暗示植物细胞壁的内源伸展就是该蛋白介导的一种生物化学过程。
In vitro cell wall elongation activity of recombinant method, soybean (Glycine max (L.) Mer.) Seedling hypocotyl cell wall-specific expansion protein activity identification and characterization results show that the elongation of soybean seedling hypocotyl growth, both with the expansion Protein activity, but also related to the increased sensitivity of cell wall to dilating protein. The elongation activity of heat-inactivated hypocotyls of soybean was restored by exogenous dilatation protein and replaced by acidic buffer (pH4.5) Expanded protein extract, stretching activity is not affected; but if the switch to a neutral buffer (pH6.8), stretching activity was depleted, and with the living cell wall, with alternating replacement of buffer repeatedly reversed; soybean and cucumber Seedling expansion proteins can cross-recombine with their thermally-inactivated cell walls. In addition, the reorganization of the cell wall elongation activity on the amphiphilic concentration and pH dependence, in line with the catalytic characteristics of the general enzyme, expansins not only play an extremely important role in the process of plant cell elongation, but also implied that the plant cell wall Source stretch is a protein-mediated biochemical process.