COMPARISON OF THE PROPERTIES OF NATIVE AND PENTAAMMINENRUTHENIUM(III)-MODIFIED XYLANASE

Two xylanases, xynA of Bacillus pumilus and xyn II of Trichoderma rees ei, were purified and then modified by the attachment of pentaammineru thenium, thereby resulting in the generation of a xylanase with veratr yl alcohol oxidase activity. Hydrolytic activity of T. reesei xyn II o n soluble xylans was unchanged by modification with pentaamminerutheni um; however modification of B. pumilus xynA greatly reduced xylan hydr olysis unless the active site of the xylanase was protected with xylos e during the modification. The presence of histidine, cysteine, or red uced glutathione during xylan hydrolysis greatly increased the xylanas e activity of the pentaammineruthenium-modified B. pumilus xylanase. G lycine, glutamic acid, methionine, or oxidized glutathione had no effe ct on xylanase activity.