Recent Topics in Chemical and Clinical Research on Glycated Albumin

Abstract

The measuring method for glycated albumin (GA) has been developed as a new glycemic control marker since the beginning of the 21st century. Since GA has an advantage in reflecting glycemic status over a shorter period than hemoglobin A1c (HbA1c), much research and many reviews have been reported. However, so far there have been few reports on glycation sites based on the tertiary structure of human serum albumin (HSA) and the comparison of glycation rates between GA and HbA1c in detail. The present review discusses how the glycation sites of lysine residues in HSA are modified with glucose, whereas the glycation sites of lysine residues are located inside of HSA as well as the direct comparison of glycation rates between GA and HbA1c using human blood. Moreover, the most recent clinical researches on GA are described.

Definition of the upper reference limit of glycated albumin in blood donors from Italy

“…For example, it has been demonstrated in vitro that the structure of the side chain of Lys525, the most frequent site of glycation, is altered in presence of fatty acids [18]. It is reasonable that in vivo different concentrations of free fatty acids, probably due to different dietary habits between Asian and Western populations, could affect glycation rate of such residue by altering the surrounding structure [19]. Notably, our population, consisting of only Caucasian subjects, was highly homogeneous for ethnicity.…”

Glycated albumin: a potential biomarker in diabetes

“…However, in the in vitro experiment by Ueda and Matsumoto, it was evidenced that GA production was about 4.5 times greater than A1C after adding known and equal concentrations of glucose in previously treated samples from healthy volunteers. These findings showed that even in identical in vitro glycation conditions, GA is produced faster than A1C (20).…”

“…By definition, glycation is a non-enzymatic spontaneous reaction in which a reducing sugar is added to a free amino group, typically lysine or arginine present within proteins, also called as Maillard reaction (Figure 1) (18)(19)(20). The first step of this reaction involves the formation of an unstable and reversible product known as Schiff base, formed by the bonding of a carbonyl group of an acyclic carbohydrate with the N-terminal amino acid (19).…”

“…Albumin structure makes it easier to perform its physiological functions, such as maintaining pH and blood osmotic pressure. Also, albumin acts as a powerful antioxidant and as the main transporter of metabolic products, ions, nutrients, drugs, hormones and fatty acids (20).…”

Thermal Fourier Transform Infrared Technique Quickly Detects an Early Onset of Glycation-Induced Conformational Changes of Human Serum Albumin

“…Human serum albumin (HSA) has been always used as a model for protein-folding and ligand-binding studies because it is the most abundant protein in human blood plasma or serum [49][50]. Glycation has been reported to alter the structure of HSA, leading to significant changes in biochemical, biophysical, and thermodynamic properties and drug-protein binding of HSA [50][51][52][53][54][55]. In our previous studies, the effects of ethanol and/or captopril on the secondary structure of HSA before and after protein binding had been investigated by FTIR determination [46][47].…”