Hideko Inoue

Enhanced separation of DNA sequencing products by capillary electrophoresis using a stepwise gradient of electric field strength.

The effect of the electric field strength gradient on the separation of DNA sequencing fragments was investigated. We demonstrate that the stepwise gradient of electric field improves the separation of DNA sequencing fragments more than 500 bases in size and diminishes the analysis time for DNA sequencing of lager DNA fragments. The use of the electric field strength gradient induces an increase in the theoretical plate number as predicted by the theoretical formulation discussed in this paper.

A one-step phosphorylation of d-aldohexoses and d-aldopentoses with inorganic cyclo-triphosphate

The phosphorylation reaction by inorganic cyclo-triphosphate (P3m) having a six-membered ring was examined for D-aldohexoses and D-aldopentoses in aqueous solution. Similar to the process for D-glucose, D-galactose, D-xylose or D-allose were phosphorylated with P3m to give stereoselectively beta-D-galactopyranosyl 1-triphosphate, beta-D-xylopyranosyl 1-triphosphate or beta-D-allopyranosyl 1-triphosphate with maximum yields of 31.3, 32.5 or 32.1%, respectively. On the other hand, in the reaction of D-ribose, D-lyxose, D-mannose or D-arabinose with P3m, the yields of beta-D-ribopyranosyl 1-triphosphate, alpha-D-lyxopyranosyl 1-triphosphate, alpha-D-mannopyranosyl 1-triphosphate or alpha-D-arabinopyranosyl 1-triphosphate were 8.0, 16.5, 9.6 or 14.1%, respectively. The phosphorylation mechanism of D-aldopyranoses with P3m was also discussed.

Stereoselective phosphorylation of branched cyclodextrins with inorganic cyclo-triphosphate

The phosphorylation by inorganic sodium cyclo-triphosphate (P(3m)) having a six-membered ring was examined for cyclomaltohexaose (alpha-cyclodextrin) and branched cyclodextrins (mono-6-O-alpha-D-glucopyranosylcyclomaltohexaose, mono-6-O-alpha-D-maltosylcyclomaltohexaose, mono-6-O-alpha-D-glucopyranosylcyclomaltoheptaose, and mono-6-O-alpha-D-maltosylcyclomaltoheptaose) in aqueous solution. For all cyclomaltooligosaccharides (cyclodextrins) studied, the 2-OH group was stereoselectively phosphorylated. In the reaction of branched cyclodextrins and P(3m), only the 2-OH on the alpha-D-glucopyranosyl group of the cyclodextrin rings was phosphorylated with maximum yields of more than 27%. The phosphorylation mechanism of branched cyclodextrins with P(3m) is also discussed.

Phosphorylation of Amino Alcohols by Inorganic cyclo -Triphosphate

The phosphorylation of amino alcohols has been achieved using cyclo-triphosphate (P3m) in aqueous solution with their maximum yields of more than 98%. The products were imidotriphosphates1 of 3-amino-1-propanol, 4-amino-1-butanol, and 5-amino-1-pentanol, which were all stable. The reaction of 1-amino-2-propanol (1A2P) with P3m produced its triphosphate derivative. Its yield increased with the reaction time to reach a maximum of 96% after 8 h, and then decreased gradually. The triphosphate derivative of 1A2P decomposed to two monophosphate derivatives via a cyclic phosphate (Scheme 1). Similar to 1A2P, the phosphorylation of 2-aminoethanol and 1-amino-2-butanol proceeded with the same mechanism. These imidotriphosphates were unstable and gradually decomposed to monophosphates because of the vicinal OH group.