Abstract In this paper, the spectral characteristics of the interaction between lead and bovine serum albumin (BSA) were analyzed by fluorescence spectroscopy, ultraviolet spectroscopy and infrared spectroscopy. The effects of pH, bovine serum albumin concentration, lead ion concentration and ionic strength on the spectra of lead ion-bovine serum albumin system were investigated, and the best testing condition is to determine the interaction between lead and BSA by testing the peak changes or displacement in the UV spectrum analysis. Fluorescence spectroscopy showed that lead ion could induce the fluorescence quenching of bovine serum albumin. The influence of lead ion on the secondary structure of protein was analyzed by infrared spectroscopy. It was found that β-angle increased, α-helix decreased and β-slice increased.

Abstract

Syringolin A is a non-ribosomal virulence factor secreted by few Pseudomonas strains. Syringolin A is an well known irreversible proteasome inhibitor and antitumor compound. The present study is focused on the extraction of Syringolin A through a non-tedious and economical process. Syringolin A is extracted from culture supernatants by the immiscible organic layer by mixing of dichloromethane or chloroform (trichloromethane). Syringolin A was identified by the characteristic peak at 350 nm by UV spectra. The compound was further characterized by Thin Layer Chromatography (TLC) with the retention value, R_f was found to be in the range of 0.78-0.83 run using a combination of solvent systems water and methanol.  The molecular weight of the compound was found to be 492.2614 g mol^-1 identified and analyzed by UHPLC–QTOF-MS analysis. Due to its significant pharmacological importance in proliferative diseases, further studies on production and optimization of these compounds are necessary.