PURIFICATION AND CHARACTERIZATION OF A XYLANASE FROM ROBILLARDA SP Y-20 GROWN ON XYLAN

An endo-1, 4-beta-xylanase (1, 4-beta-Xylanohydrolase, EC 3. 2. 1. 8) has been easily purified from culture filtrate of Robillarda sp. Y-20 by combination oi specific affinity chromatography on Bio-Gel P-6DG and gel filtration chromatography on Toyopearl HW-55S. The yield of the purified enzyme was about 40% of that in the culture filtrate. The molecular weight of the xylanase determined by SDS-PAGE was 23 400 Da. The pI value was 9.5. The optimum pH and temperature were pH 4.5-5.5 and 55 degrees C, respectively. The HPLC analysis showed that the main hydrolysate of xylooligosaccharide was xylobiose, and the enzyme had the transxylosidase activity. Km and Vmax values for xylotriose, xylotetraose, xylopentaose and xylohexose were obtained and from these data the enzyme was shown to have 5 subsites. It was found that the enzyme showed a specific affinity toward P-6DG column in the presence of xylooligosaccharides.