Tłomak P, Nowak K
Acta Biochim Pol. 1981;28(3-4):241-51.
Basing on the Chou & Fasman method (Biochemistry, 13, 222-245; 1974) and the known amino acid sequences, the alpha-helical, beta-sheet, beta-turn and random-coil regions were predicted for protein protease inhibitors. It appears that in all the inhibitors examined there is a region conserved in the vicinity of the active site, composed of one beta-turn with an adjacent beta-sheet structure, and a second beta-turn situated in the other part of the polypeptide chain and linked with the first one by disulphide bridge. Two disulphide bridges between Cys2 and Cys25, and between Cys10 and Cys21 were proposed for the squash seed inhibitor. It is suggested that the two beta-turns play an essential role in the process of trypsin inhibition by protein protease inhibitors.
基于Chou和Fasman方法（《生物化学》，第13卷，222 - 245页；1974年）以及已知的氨基酸序列，对蛋白质蛋白酶抑制剂的α螺旋、β折叠、β转角和无规卷曲区域进行了预测。在所有检测的抑制剂中，活性位点附近似乎存在一个保守区域，该区域由一个β转角和相邻的β折叠结构组成，第二个β转角位于多肽链的另一部分，并通过二硫键与第一个相连。对于南瓜籽抑制剂，提出了Cys2和Cys25之间以及Cys10和Cys21之间存在两个二硫键。有人认为，这两个β转角在蛋白质蛋白酶抑制剂抑制胰蛋白酶的过程中起着至关重要的作用。
