Purification and characterization of an α- d-glucuronidase from a thermophilic fungus, Thermoascus aurantiacus

Abstract

An α- d-glucuronidase was purified from the culture filtrates of Thermoascus aurantiacus. A simple colorimetric method for its assay is reported. The enzyme is a single polypeptide chain with a molecular weight of 118,000. It acts optimally at pH 4.5. It shows maximum activity at 65 °C. The t 1 2 at 70 °C was 40 min. It specifically cleaved the α-(1 → 2) linkage between 4- O-methyl-α- d-glucuronic acid and the xylose residue in xylan and several glucurono-xylooligosaccharides.