The nitrogen content of mature wood from lodgepole pine was 0.046% as determined by micro-Kjeldahl. Low molecular weight proteins between 14 and 21 kDa were identified in mature wood, branch wood and sap pressed from wood chips. Amino acids were quantified in acid-hydrolyzed wood samples and accounted for between 19 and 35% of the nitrogen in wood. The sapstaining ascomycete Ophiostoma piceae strain 387N produced proteolytic enzymes when grown on lodgepole pine. Proteolytic activity as measured by a spectrophotometric assay peaked after 14 days of colonization. IEF gels of extracts from colonized wood showed a major proteolytic band focusing at pH 5.2. Proteinases were detected in culture filtrates throughout growth in protein-supplemented liquid media, and appeared to hydrolyze azocoll with optimal activity at pH 8. The electrophoretic profile of proteinases in culture filtrates appeared identical to that of proteinases isolated from wood colonized by Ophiostoma piceae.

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