ENZYMATIC-HYDROLYSIS OF 7-XYLOSYLTAXANES BY XYLOSIDASE FROM MORAXELLASP

The production of large quantities of paclitaxel for use as an antican cer treatment has been a difficult problem because of the low concentr ation of the compound in yew trees (Taxus sp.) and its occurrence as p art of a mixture of other taxanes. 7-Xylosyltaxanes are major componen ts of the mixture found in the bark of the Pacific yew (Taxus brevifol ia). A bacterial strain isolated from soil and identified as a Moraxel la sp. was able to remove the xylosyl group from 7-xylosylpaclitaxel 7 -xylosyl-10-deacetylpaclitaxel, 7-xylosylbaccatin III and 7-xylosyl-10 -deacetylbaccatin III, thereby making the xylosyltaxanes available as sources of 10-deacetylbaccatin III for semisynthesis of paclitaxel. Th e activity was located in both the soluble and particulate fractions o f the cell.