Fluorescence spectroscopic analysis on interaction of fleroxacin with pepsin

Abstract

The interaction between fleroxacin (FLX) and pepsin was investigated by spectrofluorimetry. The effects of FLX on pepsin showed that the microenvironment of tryptophan residues and molecular conformation of pepsin were changed based on fluorescence quenching and synchronous fluorescence spectroscopy in combination with three-dimensional fluorescence spectroscopy. Static quenching was suggested and it was proved that the fluorescence quenching of pepsin by FLX was related to the formation of a new complex and a non-radiation energy transfer. The quenching constants KSV , binding constants K and binding sites n were calculated at different temperatures. The molecular interaction distance (r = 6.71) and energy transfer efficiency (E = 0.216) between pepsin and FLX were obtained according to the Forster mechanism of non-radiation energy transfer. Hydrophobic and electrostatic interaction played a major role in FLX-pepsin association. In addition, the hydrophobic interaction and binding free energy were further tested by molecular modeling study.

Interaction Behavior Between Niclosamide and Pepsin Determined by Spectroscopic and Docking Methods

“…The binding constants for NIC and pepsin calculated using fluorescence data and UV-vis absorption spectra were at the order of magnitude of 10 5 L·mol −1 and similar to the nobiletin-pepsin system [37]. The binding constant for fleroxaci [13] and ligupurpuroside A [36] were 10 6 L·mol −1 , and prulifloxacin [39] has the binding constant of 10 8 L·mol −1 .…”

“…Based on Eqs. (11) to (13), the values of the parameters were determined to be J=4.761×10 −15 cm 3 ·L·mol −1 , R 0 = 2.23 nm, E=0.35, and r=2.47 nm. The maximal academic critical distance for R 0 ranges from 5 to 10 nm, and the maximum academic distance between donor and acceptor for r 0 ranges from 7 to 10 nm [27].…”

“…The drug interacts with pepsin when upon entering the stomach [10]. Several reports on the interactions of several molecules with pepsin have been published [11][12][13][14][15]. Recently, Esra Maltas [16] reported the interactions of NIC with several proteins, including human serum albumin, hemoglobin, and globulin.…”

Investigation of binding between fluoroquinolones and pepsin by fluorescence spectroscopy and molecular simulation

“…Similar studies on the interaction between FQS and pepsin have been very infrequent. We previously reported the interaction of fleroxacin with pepsin, published in Biological and Chemical Luminescence . In this paper we report our further studies on the interaction of third‐generation FQS (NFX, OFX) with pepsin by fluorescence quenching, synchronous fluorescence, 3‐D fluorescence, ultraviolet−visible (UV–vis) spectra, infrared spectra and molecular simulation.…”

Magnetic core/shell Fe3O4/Au nanoparticles for studies of quinolones binding to protein by fluorescence spectroscopy

“…Quinolones are synthetic antibacterial agents with an amino alkyl substituent . They are widely used in the treatment of respiratory infections, various diseases in animal husbandry and aquaculture, and in humans . Ciprofloxacin (CPFX) and norfloxacin (NOR) are third‐generation quinolone synthetics used against bacteria .…”