论文部分内容阅读
绿豆胰蛋白酶抑制剂的Lys活性碎片由两条分别含有26及9个氯基酸残基的多肽链通过两对分子间二硫键连接而成。用DTT还原能拆分两链,其中长链含6个半胱氨酸,在空气中氧化后能恢复25％原Lys碎片活力。本文报道了此长链的化学合成和二硫键重组。合成产物的氯基酸组成与文献报道的一致。但活性明显低于天然产物。为此对绿豆抑制剂的部分序列重新进行测定,结果表明原P_2′位的Lys应为Ile按新测定序列,从长链26肽的N端和C端各去掉两个残基合成一个22肽,此22肽的活性与天然的26肽相当。此外还合成了此22肽的类似物,其活性中心的Lys残基由Ala取代,产物对胰蛋白酶和弹性蛋白酶都无抑制活力。
Lys-active fragments of the mung bean trypsin inhibitor are made by linking two polypeptide chains containing 26 and 9 chloro acid residues, respectively, between two pairs of intermolecular disulfide bonds. Two strands can be resolved by DTT reduction, where the long chain contains 6 cysteines and oxidizes in the air to restore 25% of the original Lys fragments. This paper reports the long chain chemical synthesis and disulfide bond recombination. The composition of the chloro-acid of the synthesized product is consistent with that reported in the literature. But activity was significantly lower than natural products. For this reason, the partial sequence of mung bean inhibitor was re-determined. The results showed that the Lys at the original P 2 ’should be Ile. According to the new assay sequence, two 22 residues were removed from the N-terminal and C- , This 22 peptide has the same activity as a native 26 peptide. In addition, an analogue of this 22 peptide was also synthesized. The Lys residue in its active site was replaced by Ala, and the product showed no inhibitory activity on trypsin and elastase.