Characterization of L-Galactono-1, 4-lactone Oxidase Purified from Saccharomyces cerevisiae

Saccharomyces cerevisiae에서 분리한 L-Galactono-1, 4-lactone Oxidase의 특성

  • 이승복 (서울대학교 자연과학대학 미생물학과) ;
  • 강사욱 (서울대학교 자연과학대학 미생물학과)
  • Published : 1988.03.01

Abstract

A partially purified preparation of L-galactonolactone oxidase which catalyzes the last step of L-ascorbic acid biosynthesis was obtained from Saccharomyces cerevisiae ATCc 26787. The purification procedures included Triton X-100 treatment, protamine sulfate precipitation, ammonium sulfate precipitation, DEAE-Sepharose CL-6B ion exchange chromatography, Sephadex G-150 gel filtration chromatography, and Phenyl-Sepharose CL-4B hydrophobic interaction chromatography. The optimum temperature for the enzyme activity was about $34^{\circ}C$ and the optimum pH was 6.8-7.0. The substrate specificity was confined to L-aldonolactones, L-galactono-1,4-lactone and L-gulono-1,4-lactone. An apparent Km value of 0.294mM with L-galactono-1,4-lactone as a substrate was found. By comparing the substrate specificities of this enzyme with those of isofunctional enzymes of higher plants and animals, it becomes evident that the enzyme of S. cerevisiae ATCC 26787 is rather similar to the L-gulonolactone oxidase of animals than the galactonolactone dehydrogenase of higher plants.

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