Study On The Effect Of Pulsed Electric Field On The Conformational Changes Of Protein By Fluorescence Spectroscopy And Laser Raman Spectroscopy

It was shown by our previous experiments in our laboratory that insulin, one of the intercellular molecules, was a reactive site of the bio-effects induced by Pulsed Electric Field (PEF).In order to elucidate the indirect bio-effects of PEF exerted on cells through some intercellular signal molecules, three spectroscopic methods, Fluorescence Spectroscopy, Synchronous Fluorescence Spectroscopy and Laser Raman Spectroscopy, were utilized to investigate the conformational changes of three kinds of proteins (insulin, bovine serum albumin and lysozyme) and the time-dependent effects induced by PEF.It was demonstrated by the Fluorescence Spectroscopy that the fluorescence spectra of the proteins were altered by PEF. The micro-environments of two aromatic amino acids, tyrosine and tryptophan, located in the active region of the proteins, were altered by PEF indicated by the Synchronous Fluorescence Spectroscopy. These results indicated that the structures of the proteins were changed by PEF treatment.In order to investigate whether the structures of the proteins would be affected by PEF, Laser Raman Spectroscopy was selected. Some important functional bonds and the secondary structure of proteins were studied in detail by Laser Raman Spectroscopy. The results showed that PEF has changed the vibration modes of the S-S bond, has affected the micro-environments of tyrosine, tryptophan, and phenylalanine and has changed the secondary structure, which tended to be irregular.The experimental research work in this paper would provide some useful information on the molecular level for the study on mechanism of the PEF-induced bio-effects.