Patjaraporn WongvithoonyapornChristopher BuckeJisnuson SvastiMahidol UniversityUniversity of WestminsterChulabhorn Research Institute2018-07-042018-07-041998-01-01Bioscience, Biotechnology and Biochemistry. Vol.62, No.4 (1998), 613-62113476947091684512-s2.0-0032036957https://repository.li.mahidol.ac.th/handle/20.500.14594/18328Information about the specificity of glycosidase enzymes is important since it affects their use for characterization and synthesis of oligosaccharides. Two α-mannosidases (EC 3.2.1.24), I and II, were isolated from rice beans (Vigna umbellata). The native molecular weight of both isozymes was estimated to be 329,000, but pIs of form I were 5.03-5.34 and pIs of form II were 5.46-6.20. The two isozymes were characterized in terms of optimal pH and temperature, effects of metal ions, inhibition by swainsonine and 1-deoxymannojirimycin, and kinetic parameters for p-nitrophenyl-α-D-mannopyranoside and Manα(1-2)Man. Both enzymes were more specific towards Manα(1-2)Man in both hydrolysis and synthesis, but their hydrolytic specificities towards Manα(1-3)[Manα(1-6)]Man were different. © 1998, Taylor & Francis Group, LLC. All rights reserved.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyChemistryImmunology and MicrobiologyArticleSCOPUS10.1271/bbb.62.613