Static and Dynamic Quenching of Tryptophan Fluorescence in Various Proteins by a Chromium (III) Complex

Static quenching of tryptophan fluorescence in proteins by a dioxomolybdenum(VI) thiolate complex

“…1. The results presented here complement previously published work by our group on the interaction of transition metal complexes with various proteins [3,4]. Wu and co-workers [6,29] have previously described the interaction between a highly aromatic phenylfluorone molybdenum(VI) complex with BSA and HSA.…”

“…There are three factors that influence the quenching: (i) The hydrophobicity of the ligand, (ii) the charge of the complex, and (iii) the immediate environment of the Trp in the protein [3,4]. In all three proteins, the tryptophans are surrounded by both hydrophobic and partially hydrophobic residues such as valine (BSA, HSA and lysozyme), partially hydrophobic tyrosine (BSA and HSA), leucine and phenylalanine (BSA) and isoleucine (lysozyme) [3].…”

“…The linearity of the Stern-Volmer plot and the value of the bimolecular quenching constant k q are both used to determine the type of quenching [3,4,6,29]. k q is related to 0 (Eq.…”

“…Earlier studies focused on the interaction of transition metal ions with biologically important proteins, particularly with bovine serum albumin (BSA) [1,2]. More recent studies have shifted focus to interaction of proteins with transition metal complexes, including nickel, chromium and molybdenum complexes [3][4][5][6][7]. Based on whether the ligand is hydrophobic, hydrophilic, or possess certain chemical features, the study of a wide number of complexes can give insight into how proteins behave in different chemical environments.…”

“…Serum albumins are widely studied and well-characterized proteins [3,4,[8][9][10][11][12][13][14][15][16]. The essential difference between human serum albumin (HSA) and BSA is the number of tryptophan residues (Trp).…”