Ciolkowski Michal, Rozanek Monika, Bryszewska Maria, Klajnert Barbara
Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, 141/143 Pomorska St., 90-236 Lodz, Poland.
Biochim Biophys Acta. 2013 Oct;1834(10):1982-7. doi: 10.1016/j.bbapap.2013.06.020. Epub 2013 Jul 10.
In this study the ability of three polyamidoamine (PAMAM) dendrimers with different surface charge (positive, neutral and negative) to interact with a negatively charged protein (porcine pepsin) was examined. It was shown that the dendrimer with a positively charged surface (G4 PAMAM-NH2), as well as the dendrimer with a neutral surface (G4 PAMAM-OH), were able to inhibit enzymatic activity of pepsin. It was also found that these dendrimers act as mixed partially non-competitive pepsin inhibitors. The negatively charged dendrimer (G3.5 PAMAM-COOH) was not able to inhibit the enzymatic activity of pepsin, probably due to the electrostatic repulsion between this dendrimer and the protein. No correlation between changes in enzymatic activity of pepsin and alterations in CD spectrum of the protein was observed. It indicates that the interactions between dendrimers and porcine pepsin are complex, multidirectional and not dependent only on disturbances of the secondary structure.
在本研究中，检测了三种具有不同表面电荷（正电荷、中性和负电荷）的聚酰胺-胺（PAMAM）树枝状大分子与带负电荷的蛋白质（猪胃蛋白酶）相互作用的能力。结果表明，表面带正电荷的树枝状大分子（G4 PAMAM-NH2）以及表面呈中性的树枝状大分子（G4 PAMAM-OH）能够抑制胃蛋白酶的酶活性。还发现这些树枝状大分子作为混合的部分非竞争性胃蛋白酶抑制剂起作用。带负电荷的树枝状大分子（G3.5 PAMAM-COOH）不能抑制胃蛋白酶的酶活性，这可能是由于该树枝状大分子与蛋白质之间的静电排斥作用。未观察到胃蛋白酶酶活性变化与蛋白质圆二色光谱变化之间的相关性。这表明树枝状大分子与猪胃蛋白酶之间的相互作用是复杂的、多向的，且不仅仅取决于二级结构的扰动。
