[Purification and properties of 3-hexulosephosphate synthase from facultative methylotroph Pseudomonas oleovorans]. / Ochistka i kharakteristika 3-geksulozofosfatsintazy iz fakul'tativnogo metilotrofa Pseudomonas oleovorans.

ABSTRACT

3-Hexulosephosphate synthase (HPS), the key enzyme of the hexulosephosphate cycle of formaldehyde fixation, was isolated from facultative methylotroph Pseudomonas oleovorans. Enzyme was purified 100-fold. The purification procedure involved fractionation with ammonium sulfate, gel-filtration on Sephadex G-150 and chromatography on DEAE-Sephadex A-50. The purified enzyme gave single band on analytical polyacrylamide gel electrophoresis. Optimal conditions for activity of HPS are pH 7,0, temperature 50 degrees C. The molecular weight was calculated to be 45 000 from gel-filtration experiments. HPS is active only in the presence of Mg2+ or Mn2+. Ribulose-5-phosphate is the sole acceptor of formaldehyde. Activity of the enzyme is inhibited by NADH and NADPH.