Albumin binding-site alteration in melancholic depression under pharmacotherapy: Recording with the use of subnanosecond fluorescence spectroscopy

Abstract

It is known that the conformation of human serum albumin binding sites is sensitive to pathological processes. In this work, changes in the physical–chemical properties of albumin binding sites in melancholic depression were studied. The K-35 fluorescent probe (dimethylaminonaphthalic acid N-carboxyphenylimide, CAPIDAN) was used as a reporter of these changes. It is shown that the fluorescence decay of K-35 depends on the state of the drug-binding sites of albumin. The kinetics of fluorescence decay were measured with a time resolution of approximately 30–50 ps. The parameters that characterize the fluorescence decay of K-35 in serum were reliably responsive to melancholic depression and the dynamics of its treatment. With melancholic depression, a decrease in the concentration of nonesterified long-chain fatty acids that are capable of affecting binding sites of serum albumin was observed. However, variations in the concentration of NEFA cannot be considered as a cause of the alterations of albumin binding sites. In addition to NEFA, other factors are likely to affect structural and physical-chemical properties of albumin in depression patients.