Localization of α-Galactosidase in an Alkalophilic Strain of Micrococcus

Abstract

Localization of α-galactosidase in an alkalophilic strain of Micrococcus was investigated in relation to the cell membrane as a permeability barrier. The most α-galactosidase ap-pered to be intracellular; only about 4% of α-galactosidase was released by lysozyme or freeze-thaw treatments of the whole cells. The enzyme activity was not inhibited by treatment of the whole cells with diazo-7-amino-1, 3-naphthalene disulfonic acid (NDS) which penetrated the cell wall but not the cytoplasmic membrane. The enzyme activity of the whole cells increased about four-fold by toluene-acetone treatment which caused an alteration in the membrane permeability. The enzyme in such cells became to be relatively sensitive to pH. These results showed that cell membrane played a protective role as a permeability barrier against alkaline environment.