Protein Fibrillation Induced By Guanidine Hydrochloride And Drug Metabolism Of Active Ingredient Of Chenopodium Ambrosioides L. By GC-MS

The first part of our work is about protein fibrillation induced by guanidine hydrochloride. Protein fibrillation is closely related to Alzheimer’s disease, Parkinson’s disease, prion disease and so on, and studying protein fibrillation has an important significance for understanding and controlling these diseases. In this paper, hen egg white lysozyme(HEWL) as a protein model was used to study the influence of different concentrations of guanidine hydrochloride and different speeds of stirring on the process of HEWL fibrillation induced by guanidine hydrochloride. It was found that there is an optimum concentration of guanidine hydrochloride that can generate HEWL fibrils the most. Too high or too low concentration of guanidine is not suitable for the generation of HEWL fibrils. As for the speed of stirring, it was found that it only influences on the growth rate of HEWL fibrils, but has little effect on the amount of HEWL fibrils. We then investigated the thermal stability of HEWL fibrils using thioflavin T(Th T) fluorescence and UV-vis spectroscopy. It was found that HEWL fibrils induced by guanidine hydrochloride are stable at room temperature but unstable at low temperatures. We further investigated the interaction kinetics of thioflavin T with HEWL fibrils. By performing fluorescence and UV-vis stopped-flow kinetics of thioflavin T binding to HEWL fibrils and fitting the kinetic curve, four rate constants were obtained. We can speculate that two larger rate constants can be attributed to the process of Th T binding on the regular grooves of the fibril surface, and the remaining two smaller rate constant can be attributed to the process of Th T binding in the cavity inside.The second part of our work is about the simultaneous determination of ascaridole,p-cymene and α-terpinene(internal standard is naphthalene) in rat plasma by GC-MS for studying the metabolic processes of Chenopodium ambrosioides L. in rat.