Comparative 1H NMR studies on the structural looseness of the aged (A) and non-aged (N) bovine mercaptalbumin in the alkaline region

Alteration of human serum albumin binding properties induced by modifications: A review

Albumin, a major transporting protein in the blood, is the main target of modification that affects the binding of drugs to Sudlow's site I and II. These modification of serum protein moderates its physiological function, and works as a biomarker of some diseases. The main goal of the paper was to explain the possible alteration of human serum albumin binding properties induced by modifications such as glycation, oxidation and ageing, their origin, methods of evaluation and positive and negative meaning described by significant researchers.

Spectroscopic Studies on the Molecular Ageing of Serum Albumin

Pathological states in the organism, e.g., renal or hepatic diseases, cataract, dysfunction of coronary artery, diabetes mellitus, and also intensive workout, induce the structural modification of proteins called molecular ageing or N-A isomerization. The aim of this study was to analyze the structural changes of serum albumin caused by alkaline ageing using absorption, spectrofluorescence, and circular dichroism spectroscopy. The N-A isomerization generates significant changes in bovine (BSA) and human (HSA) serum albumin subdomains-the greatest changes were observed close to the tryptophanyl (Trp) and tyrosyl (Tyr) residue regions while a smaller change was observed in phenyloalanine (Phe) environment. Moreover, the changes in the polarity of the Trp neighborhood as well as the impact of the ageing process on α-helix, β-sheet content, and albumin molecule rotation degree have been analyzed. Based on the spectrofluorescence study, the alterations in metoprolol binding affinity to the specific sites that increase the toxicity of the drug were investigated.

Stabilization of collagen by cross-linking with oxazolidine E-resorcinol

Cross-linking agents play an important part in the physical properties of collagen based biomaterials. This paper describes the stabilization of type I collagen using an oxazolidine E-resorcinol compound. It is shown by NMR and elemental analysis techniques that oxazolidine E undergoes ring opening to form an N-methylol intermediate form and then reacts with the hydrogen bonds of resorcinol. Oxazolidine E-resorcinol compound treated collagen fibers are shown by DSC analysis to be more thermally stable than simple oxazolidine E-resorcinol treated collagen. Treated collagen fibers showed shrinkage temperature around 98 degrees C implying that the oxazolidine E-resorcinol compounds impart thermal stability. Circular dichroism revealed that there is no major alteration in the structure of collagen after treatment with the compound. The study demonstrates that the involvement of hydrogen bonding and hydrophobic interaction as the principal mechanisms for stabilization of collagen by oxazolidine E-resorcinol compounds.