The assay of methylglyoxal in biological systems by derivatization with 1,2-diamino-4,5-dimethoxybenzene.
AuthorsMcLellan AC, Phillips SA, Thornalley PJ
JournalAnal Biochem
PubMed ID1456430
A procedure for the assay of methylglyoxal in biological systems is described, together with sample storage, sample processing procedures, and statistical evaluation. Specimen data are presented. Methylglyoxal was assayed by derivatization with 1,2-diamino-4,5-dimethoxybenzene and high-performance liquid chromatography (HPLC) of the resulting quinoxaline, 6,7-dimethoxy-2-methylquinoxaline, with spectrophotometric or fluorescence detection. Derivatization, solid-phase ... More
Elevated level of methylglyoxal during diabetic ketoacidosis and its recovery phase.
AuthorsTurk Z, Nemet I, Varga-Defteardarovic L, Car N,
JournalDiabetes Metab
PubMed ID16735968
'Carbonyl stress is hypothesized to be an associated complication of diabetic ketoacidosis. The production of the glycolytic intermediate methylglyoxal (MG) was followed up in 7 diabetic patients treated for ketoacidosis during pretreatment and recovery phase. Blood samples for methylglyoxal analysis were collected upon patient arrival in emergency department (0 h), ... More
Fluorimetric and high-performance liquid chromatographic determination of D-lactate in biological samples.
AuthorsOhmori S, Nose Y, Ogawa H, Tsuyama K, Hirota T, Goto H, Yano Y, Kondoh Y, Nakata K, Tsuboi S
JournalJ Chromatogr
PubMed ID1885704
'D-Lactate in biological samples was converted into a strongly fluorescent substance in a one-vial reaction. It was first converted into the pyruvate hydrazone in the presence of D-lactate dehydrogenase, an NADH-reoxidation system using diaphorase, D,L-6,8-thioctamide and hydrazine. This hydrazone was then converted into 2-hydroxy-6,7-dimethoxy-3-methylquinoxaline by 1,2-diamino-4,5-dimethoxybenzene in 1 M hydrochloric ... More
Highly sensitive determination of N-acetyl- and N-glycolylneuraminic acids in human serum and urine and rat serum by reversed-phase liquid chromatography with fluorescence detection.
AuthorsHara S, Yamaguchi M, Takemori Y, Nakamura M, Ohkura Y
JournalJ Chromatogr
PubMed ID3711202
'A simple, rapid and highly sensitive high-performance liquid chromatographic method for the determination of N-acetyl- and N-glycolylneuraminic acids in serum and urine is described. The neuraminic acids, released by hydrolysis of serum and urine, are converted in dilute sulphuric acid with 1,2-diamino-4,5-dimethoxybenzene, a fluorogenic reagent for alpha-keto acids, to highly ... More
High-performance liquid chromatography of tyrosine-containing peptides by pre-column derivatization involving formylation followed by fluorescence reaction with 1,2-diamino-4,5-dimethoxybenzene.
AuthorsIshida J, Kai M, Ohkura Y
JournalJ Chromatogr
PubMed ID3711168
'A pre-column fluorescence derivatization method is described for the high-performance liquid chromatographic determination of tyrosine-containing peptides. A tyrosyl residue in the peptide is first formylated in an alkaline medium in the presence of chloroform, and the resulting aldehyde is then converted into a fluorescent derivative by reaction with 1,2-diamino-4,5-dimethoxybenzene. The ... More
Determination of oestrogens in pregnancy urine by high-performance liquid chromatography with fluorescence detection.
AuthorsIshida J, Kai M, Ohkura Y
JournalJ Chromatogr
PubMed ID3243782
'A simple and sensitive high-performance liquid chromatographic method is described for the determination of three oestrogens (oestriol, oestrone and oestradiol) in pregnancy urine. Free oestrogens are extracted with chloroform from the urine sample. The phenolic group of each oestrogen in chloroform is formylated in the presence of an alkaline aqueous ... More
Determination of p-hydroxybestatin in human serum by high-performance liquid chromatography using fluorescence detection.
AuthorsIshida J, Kai M, Ohkura Y
JournalJ Chromatogr
PubMed ID4086547
'A high-performance liquid chromatographic method is described for the fluorimetric determination of p-hydroxybestatin (an active metabolite of bestatin) in human serum. p-Hydroxybestatin is formylated in an alkaline medium in the presence of chloroform, and converted to a fluorescent derivative with 1,2-diamino-4,5-dimethoxybenzene. This derivative is then separated on a reversed-phase column ... More
Improved preparation and structural conformation of the fluorescence labelling reagents 1,2-diamino-4,5-dimethoxybenzene and 3,4-dihydro-6,7-dimethoxy-4-methyl-3-oxo-quinoxaline-2-carbonyl chloride.
AuthorsDave KJ, Riley CM, Vander Velde D, Stobaugh JF
JournalJ Pharm Biomed Anal
PubMed ID2094431
Determination of total ascorbic acid in human serum by high-performance liquid chromatography with fluorescence detection.
AuthorsIwata T, Yamaguchi M, Hara S, Nakamura M, Ohkura Y
JournalJ Chromatogr
PubMed ID4086557
An ultramicro fluorimetric determination of total ascorbic acid in human serum using 1,2-diamino-4,5-dimethoxybenzene.
AuthorsIwata T, Hara S, Yamaguchi M, Nakamura M, Ohkura Y
JournalChem Pharm Bull (Tokyo)
PubMed ID4085079
Determination of alpha-keto acids in serum and urine by high-performance liquid chromatography with fluorescence detection.
AuthorsHara S, Takemori Y, Yamaguchi M, Nakamura M, Ohkura Y
JournalJ Chromatogr
PubMed ID4086555
A simple, rapid and highly sensitive high-performance liquid chromatographic method for the determination of alpha-keto acids in serum and urine is described. In dilute hydrochloric acid, alpha-keto acids are converted by 1,2-diamino-4,5-dimethoxybenzene into highly fluorescent quinoxalinone derivatives. The derivatives are isocratically separated simultaneously within 14 min by reversed-phase chromatography on ... More
Analysis of femtomole concentrations of alpha-ketoisocaproic acid in brain tissue by precolumn fluorescence derivatization with 4,5-dimethoxy-1,2-diaminobenzene.
AuthorsKeen RE, Nissenson CH, Barrio JR
JournalAnal Biochem
PubMed ID8238877
An extremely sensitive fluorimetric HPLC method used to determine in vivo cerebral alpha-ketoisocaproic acid (KIC) concentration with less than 2 g of tissue (e.g., a single rat brain, approximately 1.8 g) is reported. Removal of unwanted lipids and amino acids and isolation of alpha-ketoacids in an optimal derivatization buffer are ... More
Fluorogenic reactions for biomedical chromatography.
AuthorsOhkura Y, Kai M, Nohta H
JournalJ Chromatogr B Biomed Appl
PubMed ID7820282
A number of fluorogenic reactions, which have been used for HPLC detection systems by means of pre- and/or postcolumn derivatization, are surveyed with respect to both sensitivity and selectivity for the determination of biomedically important substances. For the derivatization of the substances, two types of fluorogenic reactions, fluorescence-generating and fluorescence-tagging, ... More
Fluorometric high-performance liquid chromatography of N-acetyl- and N-glycolylneuraminic acids and its application to their microdetermination in human and animal sera, glycoproteins, and glycolipids.
AuthorsHara S, Takemori Y, Yamaguchi M, Nakamura M, Ohkura Y
JournalAnal Biochem
PubMed ID3674364
A simple, rapid, and highly sensitive high-performance liquid chromatographic method is described for the determination of N-acetyl- and N-glycolylneuraminic acids in human and animal sera, glycoproteins, and glycolipids. The neuraminic acids, released by acid hydrolysis of these biological samples, are converted in dilute sulfuric acid with 1,2-diamino-4,5-methylene-dioxybenzene, a fluorogenic reagent ... More
High-performance liquid chromatographic determination of leucine-enkephalin-like peptide in rat brain by pre-column fluorescence derivatization involving formylation followed by reaction with 1,2-diamino-4,5-dimethoxybenzene.
AuthorsKai M, Ishida J, Ohkura Y
JournalJ Chromatogr
PubMed ID3235503
Fluorimetrically reactive leucine-enkephalin, one of the opioid peptides in rat brain tissues such as the striatum, cortex and hypothalamus, was assayed by reversed-phase high-performance liquid chromatography with fluorescence detection based on pre-column derivatization of the tyrosyl residue. The tyrosine-containing peptides extracted from the tissue were first formylated with chloroform in ... More
Sensitive determination of cystathionine and assays for cystathionine beta- and gamma-lyase, as well as cystathionine beta-synthase, using high-performance liquid chromatography.
AuthorsOhmori S, Nakata K, Nishihara K, Yamamoto S, Kawase M, Tsuboi S
JournalJ Chromatogr
PubMed ID1629286
Cystathionine was cleaved into 2-ketobutyric acid, cysteine and ammonia by cystathionase. 2-Ketobutyric acid was converted into 3-ethyl-2-hydroxy-6,7-dimethoxyquinoxaline (EHDQ) by reaction with 1,2-diamino-4,5-dimethoxybenzene. When EHDQ was measured in a mobile phase of pH 2.1 using high-performance liquid chromatography with ultraviolet detection, 250 pmol of L-cystathionine in 250 microliters of the reaction ... More
Accumulation of alpha-oxoaldehydes during oxidative stress: a role in cytotoxicity.
AuthorsAbordo EA, Minhas HS, Thornalley PJ
JournalBiochem Pharmacol
PubMed ID10413301
Glyoxal, methylglyoxal (MG), and 3-deoxyglucosone (3-DG) are physiological alpha-oxoaldehydes formed by lipid peroxidation, glycation, and degradation of glycolytic intermediates. They are enzymatically detoxified in cells by the cytosolic glutathione-dependent glyoxalase system (glyoxal and MG only) and by NADPH-dependent reductase and NAD(P)+-dependent dehydrogenase. In this study, the changes in the cellular ... More