EXTRACTION AND PARTIAL-PURIFICATION OF CELL-WALL-ASSOCIATED CONIFERYLALCOHOL OXIDASE FROM DEVELOPING XYLEM OF SITKA SPRUCE

The developing xylem of Picea stichensis contains an oxidase whose act ivity arises in synchrony with the initiation of lignification of thes e cells. The oxidase activity is firmly associated with the cell wall, and cell-wall preparations from developing xylem can oxidise conifery l alcohol. Although coniferyl alcohol oxidase activity could not be de tected in extracts of the cell walls obtained by washing with 1M NaCl or by digestion of the cell walls with glycanase preparations, it coul d be detected in these extracts after they had been separated using io n exchange chromatography on DEAE-Sepharose. The 1M NaCl wall extract yielded two peaks of oxidase activity whereas the glycanase-solubilise d digest contained only one peak of oxidase activity. This suggests th at only one form of oxidase is insolubilised into the xylem cell wall. Isoelectric focusing of the major cell-wall-associated oxidase gave o ne dominant cationic band with considerable smearing which suggests he terogeneity in the fine structure of the oxidase.