AMINO-ACID-SEQUENCE AND THERMOSTABILITY OF XYLANASE-A FROM SCHIZOPHYLLUM-COMMUNE

The amino acid sequence (197 residues) of xylanase A from the fungus, Schizophyllum commune, was determined by automated analysis of peptide s from proteolytic and acid cleavage. The sequence is similar to two T richoderma xylanases (approximately 56% identical amino acids), but al so shows at least 40% identities with xylanases from Bacillus subtilis , B. pumilus and B. circulans. The conserved regions of the enzyme con tain only two glutamic acid residues which implicates their possible i nvolvement in catalysis. The disulfide bond in xylanase A is not conse rved in this family. In spite of this, the B. subtilis xylanase was fo und to be more thermostable than xylanase A.