ИСТИНА

Nanomechanical approach for biochemical reaction management means that, rotation of magnetic nanoparticles (MNPs) with immobilized on them enzyme under expose of alternative magnetic field is applied for changing an enzyme structure-activity [1, 2] (fig. 1). When enzyme immobilized between two MNPs, rotation of MNP under low-frequency magnetic field (LFMF) can significantly change the enzyme structure leading to the decrease of the enzyme activity. In case of enzyme molecules immobilized on single MNP, the hydrodynamic forces changing the enzyme structure more mild. In this work we demonstratethe effect of LFMF on activity of different enzymes, immobilized on single-domain magnetite@gold nanoparticles. Previously we have shown [1] that enzymatic activity of chymotrypsin, immobilized on the aggregates of magnetite nanoparticles, decrease under impact of LFMF. To determine the mechanism of such inactivation we carried out a molecular modeling experiment where we applied stretch forces to chymotrypsin molecule. As a result of modeling we have found that enzyme catalytic center had no difference from the initial structure while the binding site has becomein more closed state. As a result of LFMF expose to immobilized on dimeric magnetite@gold nanoparticles chymotrypsin, we observed an increase in Km value while Vm remained unchanged (fig 2). Thus, experimental data of kinetic parameters measurements confirmed our data on molecular modeling. Another example of nanomechanical “devices” that could change structure-activity properties of enzyme is a single magnetic nanoparticle with enzyme, immobilized on its surface. Here, we demonstrate changing enzymatic parameters of immobilized on a single magnetite@gold nanoparticle NAD-dependent formate dehydrogenase after expose to LFMF (Table 1).