Abstract
β-Mannosidase was purified to electrophoretic homogeneity from the 20000g supernatant of guinea pig liver homogenate. A highly purified enzyme preparation was also obtained from the acetone powder. This enzyme had a pH optimum of 4.0 and molecular weights of ca. 120000 as determined by gel filtration and 110000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It was free from other glycosidase activities, as far as was tested. The enzymatic hydrolysis of o- and p-nitrophenyl β-mannosides exhibited an unusual relationship of rate to substrate concentration, indicative of the involvement of two molecules of substrate in the reaction. The rate of hydrolysis was enhanced markedly by several p-nitrophenyl compounds including p-nitrophenyl glycosides, and also by Triton X-100 and chlorinated pesticides such as aldrin.
