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It is widely accepted that oxidative stress (OS) is a major causative factor for many of the age-related dysfunctions and specific diseases. Since the oxidative stress state (OSS) of an individual depends on hereditary, dietary, and environmental factors, there is a large heterogeneity in the population that may be related to disease incidence and longevity. Hence there is a need to assess how well an individual is coping against OS. The Japan Institute for the Control of Aging (JaICA) and Genox have jointly developed a profiling technique to measure the "Oxidative Stress Profiles (JaICA-Genox OSP)" of individuals and laboratory test animals. The JaICA-Genox OSP consists of about 45 different assays measuring the levels of oxidative damage in lipids and nucleic acids, and the antioxidant defenses in the serum. In addition, several bio-markers for cardiovascular disease risk are also measured, and assays to measure specific age- and sex-related hormones in the serum and urine, and race elements in serum, urine, and drinking water are also undertaken. This overview discusses the designing of the JaICA-Genox OSP and its application in the testing of human subjects.

The site-specific oxidation of histidine residues in glycated insulin mediated by copper ions and the relationship between the oxidation sites and the steric conformation of insulin are discussed in this study. Glycated insulin was prepared by incubating native insulin with glucose in 67 mM sodium phosphate, pH 7.5, at 37 degrees C for 30 h. In the presence of micromolar concentrations of Cu2+, glycated insulin was oxidized and its fragmentation or aggregation was detected. Accompanying the fragmentation, new N-termini were generated. The residues in these N-termini were identified as alanine, proline, valine, leucine and isoleucine by comparing dansyl derivatives with standard dansyl-amino acid products. Furthermore, several oxidized products of glycated insulin were isolated using reverse-phase HPLC (P1-P3). From amino acid composition and sequence analyses, it was determined that His10 on the insulin B-chain was modified in each of these peptides, while His5 was also modified in P3. The difference in susceptibility of His10 and His5 to oxidative modification is considered to be due to easier coordination of Cu2+ with His10, which further forms a complex with the Amadori compound at B-chain Phe1 that is vicinal to His10 in the steric conformation of insulin. This complex may generate an active oxygen species, which induces the degradation of the imidazole ring at His10, leading to aggregation or fragmentation of insulin.

A novel decomposition of Amadori compound from glucose catalyzed by copper ion is discussed. The Amadori compounds prepared from glycylglycylhistidine and histidyltyrosine were oxidatively decomposed in the presence of copper ion to free peptide, N α -formyl peptide, and the sugar moieties of glucosone and arabinose. The formation of N α -formyl peptive was especially dependent on the concentrations of copper ion. Copper(II)-catalyzed autoxidative decomposition of Amadori compound to free peptide and glucosone has been clarified in our previous study, but the formation of N α -formyl peptide and arabinose was a novel pathway confirmed in this study

The oxidative damage of protein induced by the Amadori compound/copper(II) system was recently clarified (Kawakishi, S.; Okawa, Y.; Uchida, K.J. Agric. Food Chem. 1990, 38, 13-17). In the present study, we characterized a selective degradation and a possible cleavage mechanism for histidine residue found in protein mediated by the glycated peptide (Amadori compound)/copper(II) system. The main oxidized intermediate of the histidine residue, a 2-imidazolone derivative, was also confirmed in this system, which was similar to that formed in the ascorbate/copper(II) system. Although glucosone, a secondary product generated from copper(II)-catalyzed autoxidation of the Amadori compound, has been identified as a strong oxidizing agent causing protein damage, the Amadori compound itself was also confirmed to be an oxidizing agent similar to glucosone in the present study. A proposed mechanism for oxidative damage of protein mediated by autoxidation of the glycated peptide Amadori compound)/ copper(II) system is discussed.

Glycation of proteins was induced by incubation of high concentrations of d-glucose (1m) and proteins (4 mg/ml) at 40°C for 7 days. The oxidative damage of glycated protein mediated by addition of traces of metal ion in phosphate buffer (1/15m, pH 7.2) under aerated conditions was investigated. Free amino groups (mainly e-NH2 groups of lysine residues) of protein decreased during the glycation of protein but were regenerated in the oxidation of glycated protein induced with metal ion. Also in this process, an α-dicarbonyl compound was generated. Glycated protein was degraded to lower molecular weight fragments in the presence of Cu(II) but not in the absence of Cu(II). Moreover, the histidine residue of protein was selectively degradated in this oxidative process. The oxidative fragmentations of glycated protein were inhibited by EDTA or catalase, but not by urea, DMSO (scavengers of hydroxy radicals) or superoxide dismutase. A possible mechanism of oxidative fragmentation of glycated protein catalyzed by...