Lima Aurelio Resende, Juliano Luiz, Juliano Maria Aparecida
Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de São Paulo, 04044-20 São Paulo, Brazil.
Protein J. 2004 May;23(4):287-94. doi: 10.1023/b:jopc.0000027853.93513.34.
We investigated the inhibition of trypsin, human tissue (hK1) and human plasma kallikrein (HuPK), papain, and cathepsin L, B, and X by synthetic cyclic, cycloretro-isomer, cycloretro-inverso, and linear peptides derived from the C-terminal sequence of bradykinin. c(FSPFRG) and Ac-FSPFRG-NH2 were taken as the references for cyclic and linear peptides, respectively. Longer and more flexible analogs of them with addition of 2, 3, or 4 Gly and cycloretro-isomer and cycloretro-inverso analogs of c(FSPFRG) and c(GGGFSPFRG) were obtained and assayed. The susceptibility to hydrolysis of the peptides to all proteases was also examined. The highest affinities were found for c(FSPFRG) with hK1, Ac-GGFSPFRG-NH2 with HuPK, and psi (NHCO) c(fspfrG) with cathepsin L. The Ki values for cathepsin B and X with cyclic peptides were lower than those of linear peptides. The serine proteases hydrolyzed all linear and cyclic peptides, except c(FSPFRG) and c(GFSPFRG). The cysteine proteases hydrolyzed only the linear peptides, which were poor substrates. Although the Ki values obtained in the current work were in the microM range, the cyclic and cycloretro-inverso peptides seem to be a promising approach to develop efficient and resistant to hydrolysis inhibitors for the kallikreins and lysosomal cysteine proteases.
我们研究了源自缓激肽C端序列的合成环状、环逆异构体、环反式异构体和线性肽对胰蛋白酶、人组织激肽释放酶（hK1）、人血浆激肽释放酶（HuPK）、木瓜蛋白酶以及组织蛋白酶L、B和X的抑制作用。分别将环（FSPFRG）和乙酰基 - FSPFRG - NH₂作为环状和线性肽的参照。获得了添加2个、3个或4个甘氨酸的更长且更具柔性的类似物，以及环（FSPFRG）和环（GGGFSPFRG）的环逆异构体和环反式异构体类似物，并进行了测定。还检测了这些肽对所有蛋白酶的水解敏感性。发现环（FSPFRG）对hK1、乙酰基 - GGFSPFRG - NH₂对HuPK以及ψ（NHCO）环（fspfrG）对组织蛋白酶L具有最高亲和力。组织蛋白酶B和X对环状肽的Ki值低于线性肽。丝氨酸蛋白酶可水解所有线性和环状肽，但环（FSPFRG）和环（GFSPFRG）除外。半胱氨酸蛋白酶仅水解线性肽，而线性肽是较差的底物。尽管当前工作中获得的Ki值处于微摩尔范围内，但环状和环反式异构体肽似乎是开发针对激肽释放酶和溶酶体半胱氨酸蛋白酶高效且抗水解抑制剂的一种有前景的方法。
