Hyperthermostable beta-galactosidases.

摘要

A hyperthermostable beta -galactosidase having a residual activity of about 80% or above after having been treated at 90 DEG C for 120 minutes is provided. A process for producing a hyperthermostable beta -galactosidase comprising cultivating a bacterium of the genus Pyrococcus and recovering the target enzyme from the culture is also disclosed. As examples of the beta -galactosidase, three enzymes having an optimum temperature of from 80 to 95 DEG C and a stable pH value of from 5 to 10 are cited. A beta -galactosidase of the present invention is hyperthermostable and can exert its action even in the presence of sodium dodecyl sulfate