Abstract
1. As a strain of forming β-1, 3′-xylan splitting enzyme, Chaetomium globosum A2 was selected out.
2. The enzyme activities in the shaking cultural medium toward two xylans, β-1, 3′- and β-1, 4′-xylans, were observed with the growth of Ch. globosum A2. The maximum activity of β-1, 3′-xylan splitting enzyme was found after 5 days incubation in semi-synthetic medium. From a comparative test on the forming patterns of β-1, 3′- and β-1, 4′-xylan splitting enzymes with the cultivation, these enzymes were found to be independent of each other.
3. β-1, 3′-xylan splitting enzyme was prepared from the cultural broth of the mold in a highly purified state which shows a 100-fold specific activity of that of starting sample. The purified preparation did not show any activities of β-1, 4′-xylanases, cellulase and amylases.
4. β-1, 3′-xylan in a relatively low concentration was almost completely hydrolyzed by the enzyme and converted into xylose and small amount of glucose. Oligo-saccharides could not be detected as intermediary and end products by paperchromatography.
5. When various β-1, 3′-xylo-oligosaccharides were used as substrates, sugars of the higher degree of the polymerization were more readily hydrolyzed than the lower ones. And xylose and xylobiose were found to be the end products from oligo-sugars. The enzyme could not hydrolyzed xylobiose. In these cases the formation of various oligosaccharides could be demonstrated as intermediary products.
6. From the above findings, β-1, 3′-xylan splitting enzyme prepared here should be classified into xylanase and we propose the name "EXO-β-1, 3′-XYLANASE" for it.
