Luminescent probe method in the study of the interaction of glycated human serum albuminwith non-glycated human serum albumin

Background and Objectives: The development and functioning of all living beings ends with the inevitable aging process, as a result of which the activity of all organs and the body as a whole is suppressed, which leads to imminent death. Protein glycation is considered to be one of the causes of aging. This process takes place throughout life, but it intensifies with age. Protein glycation is a reaction of covalent coupling of free amino groups of proteins and reducing carbohydrates, which proceeds without the participation of enzymes and leads to disruption of protein functions. This process is unregulated, as it occurs without the participation of biological catalysts. As a result of glycation of proteins in humans, inflammatory processes occur in the body and a number of diseases such as heart attack, stroke, atherosclerosis, cataract, glycemia, Alzheimer’s disease, diabetes mellitus, etc. develop. In the tasks of medical diagnostics, methods of monitoring the state of proteins in the human body are necessary. In this regard, the work is devoted to the study of the processes of interaction of human serum albumin globules (HSA) with globules of human glycated serum albumin (gHSA). Materials and Methods: In conducting a study of the spectral-kinetic characteristics of the eosin luminescent probe in solutions of glycated and non-glycated HSA, as well as in a mixture of glycated and non–glycated HSA, an exponential dependence of the second order was used to approximate the dependencies of DF (delayed fluorescence) and PHOS (phosphorescence), and an anisotropy equation was used to assume the formation of the gHSA-HSA complex. Results: It has been found that the intensity and kinetics of quenching of delayed fluorescence and phosphorescence of the eosin fluorescent probe associated with proteins are sensitive to the ratio of glycated and non-glycated proteins in solution. To explain the increase in the intensity and lifetime of eosin phosphorescence during the transition from a solution of HSA to a mixture of HSA and gHSA, it is assumed that the globules of HSA and gHSA form a complex of the composition of gHSA-HSA, as a result of diffusion encounters. The rotational mobility of this complex is much less than the separate globules of HSA and gHSA. The formation of the complex is confirmed by an increase in the anisotropy of delayed fluorescence and phosphorescence of eosin in a mixture of HSA and gHSA. Conclusion: The obtained results of the work can be used to diagnose the presence of a complex of glycated with non-glycated proteins in human blood plasma.&nbsp