| Diabetes mellitus is a multifactorial metabolic disease with hyperglycemia.It affects the function of systemic tissues and organs,especially kidneys,eyes,and cardiovascular system.Hitherto,the prevalence and morbidity of diabetes mellitus have increased sharply.It is of great significance to investigate safe,reliable and effective hypoglycemic drugs.Dipeptidyl-peptidase Ⅳ(DPP-4)inhibitors are a type of newer hypoglycemic agents.We mainly focused on two types of DPP-4 inhibitors in this thesis,including alogliptin benzoate and linagliptin.Human serum albumin(HSA),as a main transporter in plasma,plays a very important role in transportation and metabolism of drugs in vivo.Investigation of the interaction mechanism can better understand the binding mode of drugs with HSA.The study reveals the influence of drugs on the conformation of HSA at the molecular level.It also plays a very important role in understanding the pharmacodynamics and pharmacokinetics of drugs.Furthermore,it is helpful to improve the specificity and tolerance,optimize the structure and enhance activity of drugs.In this paper,the interaction of DPP-4inhibitors with HSA was investigated using multi-spectral methods and computer simulation technique.The research content is divided into the following three parts.Fisrtly,the interaction of alogliptin benzoate with HSA was investigated using multi-spectral method and molecular docking.The interaction mechanism,the conformational effect of linagliptin on HSA and the binding sites of them were reported.The experimental results indicated that alogliptin benzoate quenched the intrinsic fluorescence of HSA through static quenching mechanism,and the van der Waals forces and hydrogen bonding contribuated to the biding process.There was only one binding site between alogliptin benzoate and HSA located at Ⅱ A subdomain of HSA.Alogliptin benzoate changed the conformation and microenvironment of HSA.It increased the polarity and decreased the hydrophobicity of HSA.Secondly,the interaction mechanism of linagliptin with HSA was investigated using fluorescent and UV–vis absorption spectroscopy.Results revealed the presence of static quenching and non-radiative energy transfer between linagliptin and HSA.The electrostatic force drove the interaction process.There was only one binding site between linagliptin with HSA.Moreover,UV–vis,synchronous fluorescence,circular dichroism and three-dimensional fluorescence spectroscopy were used to explore the conformational effect of linagliptin on HSA.It indicated that linagliptin changed the conformation and microenvironment of HSA by increasing the polarity and decreasing the hydrophobicity.Furthermore,the molecule docking and competitive site experiment were used to investage the binding area.The results indicated that binding site of linagliptin with HSA located at ⅡA subdomain.Forty-two structural analogues of linagliptin with known activity were used to molecular alignment and modeling by three-dimensional quantitative structure-activity relationship(3D-QSAR).By using constructed model,twelve new compounds were designed with higer activity.It provided a reference on structure optimization of linagliptin. |
