The pathway via D-galacturonate/L-galactonate is significant for ascorbate biosynthesis in Euglena gracilis: identification and functional characterization of aldonolactonase.

ABSTRACT: We have previously proposed that Euglena gracilis possesses a pathway for the production of ascorbate (AsA) through d-galacturonate/L-galactonate as representative intermediates ( Shigeoka, S., Nakano, Y., and Kitaoka, S. (1979) J. Nutr. Sci. Vitaminol. 25, 299-307 ). However, genetic evidence proving that the pathway exists has not been obtained yet. We report here the identification of a gene encoding aldonolactonase, which catalyzes a penultimate step of the biosynthesis of AsA in Euglena. By a BLAST search, we identified one candidate for the enzyme having significant sequence identity with rat gluconolactonase, a key enzyme for the production of AsA via d-glucuronate in animals. The purified recombinant aldonolactonase expressed in Escherichia coli catalyzed the reversible reaction of

SUBMITTER: Ishikawa T 

PROVIDER: S-EPMC2662179 | biostudies-literature | 2008 Nov

REPOSITORIES: biostudies-literature