Takashi Niitsu

Imidazolidinium-based robust crypt with unique selectivity for fluoride anion

A new imidazolidinium based receptor exhibiting unique affinity and high selectivity for fluoride anion through steric requirements and the cooperativity of multiple intramolecular binding, has been designed, synthesized and structurally characterized.

Production of l-[3-13C] serine from [13C] formaldehyde and glycine using an enzyme system combined with tetrahydrofolate regeneration

Abstract 13 C-labelled l -serine was efficiently produced from [ 13 C] formaldehyde and glycine by using partially purified l -serine hydroxymethyltransferase from Methylobacterium extorquens JCM 2804, tetrahydrofolate and a tetrahydrofolate regeneration system. The tetrahydrofolate regeneration system allowed efficient l -serine production and direct use of dihydrofolate easily prepared from folic acid. A tetrahydrofolate concentration of more than 0.020% was necessary for efficient production. Eighty seven % of the amount of [ 13 C] formaldehyde consumed, i.e. , the difference between the total amount of formaldehyde fed and the amount of formaldehyde remaining in the reaction mixture, was used for the incorporation into l -[ 13 C] serine. Seventy two mg of added glycine was converted to l -serine when 100 mg of glycine was contained in 11.2 ml of the final reaction mixture. The l -serine was confirmed to be l -[3- 13 C]-serine by negative fast atom bombardment mass spectrometry (FAB-MS) and 13 C-nuclear magnetic resonance spectrometry (NMR) analysis.