An enzyme producing isoprimeverose from xyloglucan fragment oligosaccharides has been purified to the electrophoretically pure state from a commercial enzyme preparation of Aspergillus oryzae (Sanzyme 1000). The purified enzyme showed approximately 1, 280-fold increase of the specific activity over the original preparation.
The purified enzyme was shown to be an oligomeric protein consisting of two subunits, each of which had a molecular weight of 115, 000. The enzyme showed the highest activity at pH 5.0 and 60°C, and was stable in the pH range from 5 to 7 and at up to 50°C. The isoelectric point of this enzyme was pH 3.9. The puri-fied enzyme was highly specific for xyloglucan fragment oligosaccharides and split off isoprimeverose units from the non-reducing end of the backbone of the substrate.
The Japanese Biochemical Society