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The oxidative modification of proteins is believed to play a critical role in the etiology and/or progression of several diseases. alpha-Aminoadipic semialdehyde (AAS) and gamma-glutamic semialdehyde (GGS) residues represent major oxidized amino acids generated in oxidized proteins. This paper describes a novel procedure for the specific and sensitive determination of AAS and GGS after their reductive amination with sodium cyanoborohydride and p-aminobenzoic acid, a fluorescence reagent, to their corresponding derivatives, followed by a high-performance liquid chromatography (HPLC) analysis. This fluorescent labeling of protein-associated aldehyde moieties is a simple and accurate technique that may be widely used to reveal increased levels of oxidatively modified proteins with reactive oxygen species during aging and disease.

Since variant Creutzfeldt-Jakob disease (vCJD) has been suspected to be attributable to the infectious agents associated with bovine spongiform encephalopathy (BSE), it is important to prevent the transmission of pathogenic forms of prion protein (PrP Sc ) through contaminated feeding materials such as meat and bone meal (MBM). Here, we demonstrate that the Maillard reaction employing a formulation of glucose in combination with sodium hydrogen carbonates effectively reduced the infectivity (approximately 5.9-log reduction) of a scrapie-infected hamster brain homogenate. In addition to a bioassay, a protein misfolding cyclic amplification (PMCA) technique, in which PrP Sc can be amplified in vitro , was used as a rapid test for assessing PrP Sc inactivation. The PMCA analysis also indicated that the PrP Sc level in the infected material significantly decreased following the Maillard reaction. Therefore, the Maillard reaction can be employed for the decontamination of large amounts of byproducts such as MBM.

The lysine residue of bovine serum albumin was deaminated to allysine (α-aminoadipic-δ-semialdehyde) during the incubation with glucose, 3-deoxyglucosone (3-DG), and methylglyoxal (MG) in the presence of Cu2+ at a physiological pH and temperature but not with glyoxal. Further, glucose, 3-DG, and MG oxidatively deaminated benzylamine to benzaldehyde in the presence of Cu2+. The formation of benzaldehyde was greatest with Cu2+, and was accelerated in the presence of oxygen. EDTA, catalase, and dimethyl sulfoxide (DMSO) significantly inhibited the oxidation. Analysis of plasma proteins revealed significantly higher levels of allysine in streptozotocin (STZ)-induced diabetic rats compared with normal controls. From these findings, we propose a novel mechanism for the oxidative modification of proteins in diabetes via the Maillard reaction.

Isolation and structure analysis of two amino acids from bovine ligamentum nuchae elastin hydrolysates revealed the presence of pyridine cross-links in elastin. The structures of these amino acids were determined to have 3,4,5- and 2,3,5-trisubstituted pyridine skeletons both with three carboxylic acids and a mass of 396 (C18H28N406) identified as 4-(4-amino-4-carboxybutyl)-3,5-di-(3-amino-3-carboxypropyl)-pyridine and 2-(4-amino-4-carboxybutyl)-3,5-di-(3-amino-3-carboxypropyl)-pyridine. We have named these pyridine cross-links desmopyridine (DESP) and isodesmopyridine (IDP), respectively. Structure analysis of these pyridine cross-links implied that the formation of these cross-links involved the condensation reaction between ammonia and allysine. The elastin incubated with ammonium chloride showed that DESP and IDP levels increased as the allysine content decreased. DESP and IDP were measured by high pressure liquid chromatography (HPLC) with UV detection and were found in a variety of bovine tissues. The DESP/desmosine (DES) and IDP/isodesmosine (IDE) ratios in aorta elastin were higher than in other tissues. DESP and IDP contents in human aorta elastin were found to be gradually increased with age. The concentration of IDP was significantly elevated in aorta elastin of rat with chronic liver cirrhosis induced by carbon tetrachloride (mean ± S.D.; 11.1 ± 0.9 nmol/mg elastin) when compared with normal rats (5.9 ± 1.5 nmol/mg elastin). Although DESP and IDP are present at only trace concentrations in the tissue elastin, these pyridine cross-links may be useful biomarkers for the aortic elastin damaged by ammonia.

An ion-paired high-performance liquid chromatographic method for the determination of aldosine, which is derived from the aldol crosslink of both elastin and collagen, is described. Aldosine was determined as the pyridine derivative 6-(3-pyridyl) piperidine-2-carboxylic acid, which was synthesized by oxidative decarboxylation of aldosine using iron(III). This method does not require radioisotopes to label the aldol crosslink. In addition, pyridinium crosslinks such as desmosines can also be measured.

Two new fluorescent crosslinking amino acids named oxodesmosine and isooxodesmosine were isolated from bovine aorta elastin. These amino acids have unique structure, both N-substituted dihydrooxopyridine skeletons.

A new pentafunctional cross-linking amino acid, termed allo-desmosine, was isolated from bovine ligamentum nuchae elastin. This compound was a very hygroscopic, white amorphous solid with a faint yellow tinge, soluble in aqueous solvents but not dry methanol; it was characterized by UV, FAB mass and NMR spectroscopy. The compound was shown by UV and 1H-NMR to have a pyridinium ring structure similar to desmosine. Mass spectral analysis indicated a parent compound with a mass of 655. We postulated that it arose by condensation of a reduced aldol condensation product of allysine, allysine and lysine.

The colour stability of shisonin, a red pigment isolated from the leaves of a perilla (Perilla ocimoides L. var. crispa Benth ), was studied in model systems. At pH less than 6, the absorbance of shisonin in solution decreases with increase in pH. The degradation of shisonin in buffers at both pH 3 and 4 followed first-order reaction kinetics. Fructose, sucrose, metal cations Cu ++ and Fe +++ , hydrogen peroxide, oxygen and daylight affected the degradation rate of shisonin, while glucose, lactose, glycine and leucine had essentially no effect on the degradation rate .

Formation of a glycosidic anhydro-disaccharide from heated lactose was studied. Lactosan, 4-O-β- d -galactopyranosyl -1,6- anhydro -β- d -glucopyranose , was isolated from the lactose pyrolysate obtained by heating in vacuo. It was deduced that the lactosan was a reaction intermediate and contributed to the formation of 1,6-anhydro-β- d -glucopyranose and polysaccharide.

Sept phases stationnaires sont utilisees: DEGS, SE-30, OV-17, SE-52, QF-1, PEG-20M et Apiezon M

1. 1. The egg yolk of Japanese quail contained 29.8% total lipids, of which 67.5% were neutral lipids, 32.5% polar lipids. 2. 2. The neutral lipids were predominantly triglyceride, lesser amounts of sterol ester and sterol, with, in decreasing amounts, free fatty acid, diglyceride, and monoglyceride; polar lipids were mainly phosphatidyl choline, phosphatidyl ethanolamine and sphingomyelin. 3. 3. The principal fatty acids of the total lipids and triglyceride were 18:1, 16:0, 16:1, 18:0, and 18:2, with a predominance of 18:1 and 16:0. The sterol ester and phospholipids, except sphingomyelin, contained a higher percentage of polyunsaturated acids than the other lipid fractions. 4. 4. From the viewpoint of biosynthesis of egg yolk lipids, the abundance of polyunsaturated fatty acids was of some interest since the higher content of these acids have not been reported in the corresponding fractions of the chicken eggs.

A method for the isolation of ketoses and nonreducing sugars from sugar mixtures by the addition of aniline, in the presence of acetic acid as a catalyst, is described. The aldoses react readily to form aniline derivatives, which are then removed using standard procedures: extraction with organic solvents, and treatment with activated charcoal and with a cation-exchange resin. The ketoses and nonreducing sugars are retained in aqueous solution.

The following condensation products of 5-(hydroxymethyl)-2-furfuraldehyde (HMF) with glucose, galactose or lactose were identified in the reaction mixtures heated under various conditions: HMF-β-d-galactofuranoside (1), HMF-α-d-galactofuranoside (2), HMF-d-galactopyranoside (3), HMF-d-glucopyranoside (4), HMF-d-glucofuranoside (5), 4′,6′-O-[5-(hydroxymethyl)-2-furfurylidene]-lactose (6), 4′,6′-O-[5-(hydroxymethyl)-2-furfurylidene]-HMF-lactoside (7). Compounds (3) and (5) were detected in galactose and glucose, respectively, heated at 215°C for 10 h by thin-layer chromatography. Compound (6) was suggested to exist in lactose heated at 215°C for 10 h, by thin-layer chromatography. Compound (5) was also detected in a commercial caramel prepared by heating of millet honey with ammonium sulfate and a commercial caramel candy.