自组装双亲短肽（ｓｅｌｆａｓｅｍｂｌｉｎｇａｍｐｈｉｐａｔｈｉｃｐｅｐｔｉｄｅｓ，ＳＡＰｓ）是一类亲疏水氨基酸按一定规律分布，具有自聚合效应的氨基酸短肽，融合在酶蛋白Ｎ端时，具有促进表达和稳定化的功能。以自组装双亲短肽Ｓ１（ＡＥ ＡＥＡＫＡＫＡＥＡＥＡＫＡＫ）为出发序列，与来源于ＢａｃｉｌｕｓｓｐＷＳＨＢ０４０２的碱性果胶酶（ａｌｋａｌｉｎｅｐｏｌｙｇａｌａｃｔｕｒｏｎａｔｅ ｌｙａｓｅ，ＰＧＬ）组成的融合酶为模式蛋白，考察ＳＡＰｓ的氨基酸组成及ＳＡＰｓ融合蛋白内部连接肽（ｌｉｎｋｅｒｐｅｐｔｉｄｅ）对 ＰＧＬＳＡＰ融合酶的表达量的影响。结果显示，含有较弱疏水性的甘氨酸和丙氨酸残基的ＰＧＬＳ１突变体可使融合酶正常表达，其中，含有组氨酸的ＰＧＬＳ１ｖ１具有相对最高的胞外酶活，较野生型提高了９倍，较ＰＧＬＳ１提高了１５倍。连接肽方面，与刚性连接肽相比，含有柔性连接肽的融合酶具有更高的胞外酶活，含有（ＧＧＧＧＳ）３ 的 ＰＧＬＦＳ１融合酶胞外酶活是野生型的１４倍。上述结果表明，ＳＡＰｓ的氨基酸组成及融合蛋白之间的连接肽对 ＰＧＬ融合酶的表达具有重要影响。

Self-assembling amphipathic peptides (SAPs) are a kind of functional peptides, which have alternating hydrophilic and hydrophobic residues and can affect the thermal stability and catalytic properties on the fused enzymes. In this study, several SAPs fusion protein which comprised S1 peptide (AEAEAKAKAEAEAKAK) derivatives and Bacillus sp.WSHB04-02 alkaline polygalacturonatelyase (PGL) or PGL-S1 with different linker peptides were constructed, and the effect of the linker peptides and the amino acids composition of SAPs on expression quantity the fusion enzymes were examined. The results showed that the hydrophobicity of hydrophobic amino acids make a critical difference on the expression quantity of PGL. The SAPs which contained the weaker hydrophobic alanine and glycine residues could make the fused protein expressed normally. The PGL-S1v1 possessed the relative high crude enzyme activity. Compared with the PGL and PGL-S1, the extracellular enzyme activity was increased by9-fold and 1.5-fold, respectively. As for the linker peptides, the flexible linkers enhanced the extracellular expression of the fusion protein more efficiently compared with the rigid counterparts. Of which the crude enzyme activity of PGL-F-S1 with flexible linker peptide were increased 14-fold than that of PGL. These results suggested that the amino acids composition of SAPs and the flexibility of the linker peptides could effectively affect the expression quantity the fusion protein.