The fatty-acid-induced conformational states of human serum albumin investigated by means of multiple co-binding of protons and oleic acid

Abstract

The binding of oleic acid to human serum albumin causes progressive changes in (a) the pK of some amino acid residues, as detected by pH-stat titration and (b) the induced molar ellipticities of albumin-bound drugs (diazepam and oxyphenbutazone), as measured by c.d. It is concluded that albumin undergoes several conformational transitions as the amount of oleic acid bound increases from 0 to about 9 molecules/ molecule of protein. At least three different conformations of the protein seem to be involved. These conformations can be linked with the three classes of oleic acid-binding sites on albumin.

Evaluation of the Interactions between Human Serum Albumin (HSA) and Non-Steroidal Anti-Inflammatory (NSAIDs) Drugs by Multiwavelength Molecular Fluorescence, Structural and Computational Analysis

“…Let us note that the diversity of binding modes found for these compounds may be related to the plasticity of this pocket, as noted in the different orientations adopted for the side chain of Trp214, which can adopt two distinct conformations related by a rotation of 180 degrees around the Cβ-Cγ bond ( Figure 8 ). Therefore, it may be speculated that binding to site IIC may require a dynamical adjustment of the protein, leading to a kinetically slower binding that presumably may involve a preliminary binding to site IIA and the subsequent migration to site IIC, or alternatively the selective binding to distinct conformational states of the protein [ 27 , 28 , 29 ].…”

Influence of Endogenous Substances on Site-II to Site-I Displacement of Diclofenac Bound to Albumin in the Aqueous Humor of Patients with Cataract

“…Therefore, the unexpected phenomenon that we observed-the inhibition of diclofenac binding by PB-might be due to the presence of endogenous substances in the pooled aqueous humor sample. Thus, we selected the endogenous substances in the pooled aqueous humor based on the following perspectives and measured their concentration: 1) the inhibition of diclofenac binding by FFAs, 14) amino acid, 15) and lactic acid; 16) 2) conformational change induced by FFAs; 17) 3) antioxidation by ascorbic acid; 18) 4) degeneration by urea; 19) and 5) glycosylation by glucose; 20) these affect the binding sites of albumin. Concentrations of the endogenous substances are shown in Table 1.…”