Purification and kinetic properties of guinea pig liver .BETA.-mannosidase.

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Abstract
.beta.-Mannosidase was purified to electrophoretic homogeneity from the 20,000 g supernatant of guinea pig liver homogenate. A highly purified enzyme prepration was also obtained from the acetone powder. This enzyme had a pH optimum of 4.0 and MW of approximately 120,000 as determined by gel filtration and 110,000 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 .beta.-mannosides exhibited an unsual relationship of rate to substrate concentration, indicative of the involvement of 2 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.