Abstract
This paper describes the specificity of Aspergillus niger 5-16 α-galactosidase toward various oligosaccharides having terminal galactose or stub galactose or both on the oligosaccharide. The galactosidase rapidly hydrolyzed p-nitrophenyl-α-D-galactopyranoside, but hardly liberated galactose from melibiose, manninotriose, 63-α-D-galactosylmannotriose, etc. On the other hand, the enzyme tore off the stub galactoses attached to the inner mannoses of the main-chain of galactomanno-oligosaccharides, but not the terminal galactoses attached to the non-reducing-end mannoses of the main-chain. Thus, the substrate specificity of A. niger 5-16 α-galactosidase is quite different from that of Mortierella vinacea α-galactosidase.
