Paiva P M G, Oliva M L V, Fritz H, Coelho L C B B, Sampaio C A M
Departamento de Bioquímica, CBB/UFPE, Av. Moraes Rego, S/N, Cidade Universitária, Recife-PE, CEP 50670-420, Brazil.
Phytochemistry. 2006 Mar;67(6):545-52. doi: 10.1016/j.phytochem.2005.12.017. Epub 2006 Jan 26.
Two Bowman-Birk type trypsin inhibitors (CmTI(1) and CmTI(2)) were purified from Cratylia mollis seeds by acetone precipitation, ion exchange, gel filtration and reverse-phase chromatography. CmTI(1) and CmTI(2), with 77 and 78 amino acid residues, respectively, were sequenced in their entirety and show a high structural similarity to Bowman-Birk inhibitors from other Leguminosae. The putative reactive sites of CmTI(1) are a lysine residue at position 22 and a tyrosine residue at position 49. Different reactive sites, as identified by their alignment with related inhibitors, were found for CmTI(2): lysine at position 22 and leucine at position 49. The dissociation constant K(i) of the complex with trypsin is 1.4 nM. The apparent molecular mass is 17 kDa without DDT and 11 kDa with reducing agent and heating.
通过丙酮沉淀、离子交换、凝胶过滤和反相色谱法从绒毛豆种子中纯化出两种鲍曼-伯克型胰蛋白酶抑制剂（CmTI(1)和CmTI(2)）。CmTI(1)和CmTI(2)分别含有77和78个氨基酸残基，已完成全序列测定，并且与其他豆科植物的鲍曼-伯克抑制剂具有高度的结构相似性。CmTI(1)的推定活性位点是第22位的赖氨酸残基和第49位的酪氨酸残基。通过与相关抑制剂比对确定，CmTI(2)具有不同的活性位点：第22位的赖氨酸和第49位的亮氨酸。与胰蛋白酶形成的复合物的解离常数K(i)为1.4 nM。在无DDT的情况下，表观分子量为17 kDa；在有还原剂和加热的情况下，表观分子量为11 kDa。
