Protuberic acid-hydrolytic enzyme in Kobayasia nipponica and characterization of the hydrolytic products

When the cold water-extract of Kobayasia nipponica containing a glycuronan, protuberic acid (PA), was allowed to stand at room temperature, PA was hydrolyzed. The optimum conditions for this PA-hydrolysis were 37 degrees C and pH 4-5 in 0.1 M acetate buffer. Characterization of the hydrolytic products was performed by chemical analysis, and by 1H- and 13C-NMR spectroscopy. They were identified as D-GlcUA and O-(alpha-L-IdUAp)-(1-4)-D-GlcUA. These results suggest that PA-hydrolytic enzyme(s) include at least endo-beta-D-glucuronidase.