Identification and Characterization of Novel Intracellular α-Xylosidase in Aspergillus oryzae

• Published in: Journal of applied glycoscience : JAG Vol. 70; no. 4
• Main Authors: Matsuzawa, Tomohiko, Nakamichi, Yusuke, Shimada, Naoki
• Format: Journal Article
• Language: Japanese
• Published: Tsukuba Japan Science and Technology Agency 01.01.2023
• Subjects: Aspergillus oryzae; Glycosidases; Glycoside hydrolase; Intracellular; Oligosaccharides; Substrate specificity; Substrates; Xyloglucan; Xyloglucan oligosaccharides; Xylopyranoside; Xylosidase
• ISSN: 1344-7882; 1880-7291
• DOI: 10.5458/jag.jag.JAG-2023_0007

α-Xylosidase releases xylopyranosyl side chains from xyloglucan oligosaccharides and is vital for xyloglucan degradation. Previously, we identified and characterized two α-xylosidases, intracellular AxyA and extracellular AxyB, in Aspergillus oryzae. In this study, we identified a third α-xylosidase, termed AxyC, in A. oryzae. These three A. oryzae α-xylosidases belong to the glycoside hydrolase family 31, but there are clear differences in substrate specificity. Both AxyA and AxyB showed much higher hydrolytic activity toward isoprimeverose (α-D-xylopyranosyl-1,6-glucose) than p-nitrophenyl α-D-xylopyranoside. In contrast, the specific activity of AxyC toward the p-nitrophenyl substrate was approximately 950-fold higher than that toward isoprimeverose. Our study revealed that there are multiple α-xylosidases with different substrate specificities in A. oryzae.