The University of Tokyo · Chemistry
Professor Makoto Tsunoda's research lab specializes in the development of highly sensitive analytical methods for bioactive molecules, particularly thiols, catecholamines, and neurotransmitters. The lab focuses on advanced separation techniques such as HPLC, capillary electrophoresis, and column-switching systems combined with selective detection methods like fluorescence and electrochemical detection. Key research directions include the quantification of endogenous compounds in biological fluids, enzyme activity assays (e.g., COMT), and chiral analysis of amino acids and neurochemicals. The work emphasizes methodological innovation for improved sensitivity, selectivity, and applicability in biological and physiological studies.
Figures are computed from collected data and may differ slightly.
A method for analyzing biothiols based on high-performance liquid chromatography (HPLC)-fluorescence detection under hydrophilic interaction chromatography (HILIC) conditions has been developed. Thiols were derivatized with nonfluorescent ammonium 7-fluoro-2,1,3-benzoxadiazole-4-sulfonate (SBD-F), which selectively reacts with the thiol groups to furnish the corresponding fluorescent SBD-thiols. Among the six different kinds of HILIC columns examined, the ZIC-HILIC column with sulfobetaine group
A simple method for the determination of catecholamines (norepinephrine, epinephrine, and dopamine) in urine is described. The analytes were extracted from urine by extraction using a monolithic silica disk-packed spin column. The spin column has a phenylboronate moiety, which forms a stable negatively charged complex with cis-hydroxyl groups of catecholamines. The extraction recoveries of catecholamines were above 92.2%. The extracted catecholamines were separated on a reversed-phase column fol
We have previously reported a highly sensitive method for the measurement of catechol-O-methyltransferase (COMT) activities in rat erythrocytes with norepinephrine (NE), an endogenous native substrate, using high-performance liquid chromatography (HPLC)-fluorescence or peroxyoxalate chemiluminescence reaction detection. Applying this method to COMT activities in rat liver and kidney, known to have the highest activities of all organs, the optimum reaction conditions were investigated. Under the
We have previously reported that methylation of catecholamines by catechol-O-methyltransferase (COMT) was attenuated in spontaneously hypertensive rats (SHR) with acute hypotension as compared with that of Wistar-Kyoto (WKY) rats. Here we examined the soluble (S-) and membrane-bound (MB-) COMT activities and COMT protein in the liver, kidney, and erythrocytes in both strains. Both the activities and the amounts of MB-COMT in the liver were lower in SHR than in WKY rats, but no such trend was fou
Enantiomeric separation and detection of D,L-aspartic acid (Asp) derivatized with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) by capillary electrophoresis (CE) using modified cyclodextrins as chiral selectors was studied. Heptakis(2,3, 6-tri-O-methyl)-beta-cyclodextrin(TM-beta-CD) was most effective for enantiomeric separation of NBD-D,L-Asp with optimum conditions of 30 mM TM-beta-CD in 50 mM phosphate buffer (pH 4.0) and the limit of detection (LOD) attained was 100 nM for each enantiomer. T
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