Alpha-glucuronidase involved in the hydrolysis of xylan, a major structural heterogeneous polysaccharide found in plant biomass representing the second most abundant polysaccharide in the biosphere, after cellulose. It catalyzes the cleavage of alpha-1,2-glycosidic bond of the 4-O-methyl-D-glucuronic acid side chain of xylan and releases 4-O-methylglucuronic acid from xylan. Hydrolysis of (1->2)-alpha-D-(4-O-methyl)glucuronosyl links in the main chain of hardwood xylans. The metal cations Ni(2+), K(+) and Zn(2+) show some inhibition of the activity, and Ag(+), Hg(2+) and Cu(2+) shows very significant inhibition even at relatively low ion concentrations. Optimum pH is 5.5-6. It retains about 40% of its activity at pH 4.5 and 7.5. Optimum temperature is 65 degrees Celsius. The enzyme is stable up to 70 degrees Celsius and lost 70% of its activity at 75 degrees Celsius. Homodimer. Belongs to the glycosyl hydrolase 67 family.