胰酶的小肽类抑制剂的研究

利用噬菌体表面展示15肽库技术对胰酶抑制剂进行了3轮特异性的筛选.从中得到18个不同的肽序列,与胰酶天然抑制剂活性部位比较,对抑制剂的活性序列进行了分析.根据分析结果合成了1个9肽,其抑制常数为89±10μmol/L.

Studies on the Peptidic Inhibitors of Trypsin

Trypsin was screened in a phage displayed 15-residue peptide library for three rounds basically according to the method described by G. P. Smith. To improve the effectiveness and specificity of screening, the mothod was modified as follows. (1) During the whole screening, trypsin was kept in 0.1mol/L HEPES/20 mmol/L CaCl₂buffer(pH7.6) in order to remove most(if not all) of trypsin substrates from the peptide library.(2) Phages binding to the active site of trypsin(potential inhibitors of trypsin) were specifically eluted with trypsin inhibitor BPTI. After three rounds of screening, the potential inhibitors of trypsin were riched. Eighteen of the insert peptide sequences were determined. The result showed that the P1' residues and residues flank the scissile bonds in inhibitors are both important for the inhibitory activities. Compared with the naturally occurring inhibitors of trypsin, a 9-residue peptide DGCCRAQIT was synthesized and its inhibition constant to trypsin was determined to be 89±10 mmol/L.