## 4 Summary  
In this study, we discuss the conformational changes in trypsin inhibitors at different amounts and different directions of applied electrostatic fields using a molecular dynamics simulation to find the change law of the protein's secondary structure, and the simulation results found that the external electrostatic field had a huge impact on protein conformation changes. When an electric field of 0.5 v/nm was applied to a one-way electric field, the chain region of the protein (residues 4-19) and the folding region (residues 139-149) began to deform, and the latter changed insignificantly. When an electric field of 0.5 v/nm (0.354 v/nm) was applied simultaneously in multiple directions, the new folding region (residues 61-88) and the chain region (residues 169-180) also changed successively. In the next three segments, residues 61-88 and residues 139-149 were expanded to a certain extent in molecular dynamic simulations, and residues 169-180 gradually expanded into flat protein chains. We calculated parameters such as RMSD, dipole moment analysis, hydrogen bonding, SASA, etc. The analysis of the number and length of hydrogen bonds showed that some of the structures inside the protein were deconstructed under the action of the electric field; the hydrogen bonds between some protein molecules were broken, and new hydrogen bonds formed with the water molecules. The numerical changes in SASA also confirmed this conclusion, and under the action of the electric field, the area of hydrophilic regions and the hydrophobic regions of proteins increased due to conformational changes. RSMD indicates that the protein as a whole and the analyzed fragments spatially shifted after energization, and the conformation changes deviated from their original positions. The analysis of dipole moments shows that proteins are coupled to the electric field direction under the action of the electric field, and the coupling effect  
Figure 11: Myeloma cells’ state under different levels of electric field intensity. Figure 10: Experimental apparatus for the effect of the pulsed electric field on biological tissue. and speed of each direction are different. In summary, the direction and quantity of the electric field have different effects on the secondary structure of proteins. The greater the electric field intensity, the more intense the movement of protein molecules and the more likely conformational changes occur. While the electric field intensity is the same, the reaction results of protein molecule motion under the action of the electric field in different directions are also different. In the actual experiment of myeloma cells under a pulsed electric field, the experimental results show that the phospholipid membrane structure has a certain resistance to the pulsed electric field below 1.5 kV/cm. When the electric field intensity is higher than this value, the pulsed electric field causes irreversible damage to the membrane structure. Due to the complex structure of phospholipids and proteins, the specific molecules destroyed by a pulsed electric field need to be further studied. The subject of this paper is a trypsin inhibitor, which has the effect of controlling the catalytic rate and effect of trypsin. Through the study and calculation of the behavior of trypsin inhibitors under the electric field, it is possible to accurately control the conformational changes in trypsin inhibitors, thereby changing the properties of proteins and achieving accurate control of the catalytic process of trypsin, which is of great value for antimicrobial and insect pests [37], food and drug production [38], health maintenance [39], and disease prevention [15]. M.H. : Multidirection complex electric field simulation of protein; Calculation and analysis of protein parameters such as RMSD and hydrogen bond; Writing--Original Draft; K.Z. : Simulation experiments of different electric fields in X-axis direction of protein No. 4H9W, Writing--Original Draft; F.C. : VMD visualization of protein molecular motion trajectories; Y.J.