Localization of beta-galactosidase in cells of Escherichia coli by low voltage electron bombardment.

By using low voltage electrons to bombard dried cells of Escherichia coli, the inactivation of the enzyme beta-galactosidase as a function of depth of electron penetration has been studied. There is little inactivation for a penetration of 100 A, but considerable for a penetration of 300 A. An analysis of the data for six initial electron energies shows that there exist outer and inner bounds of the enzyme region which are approximately 300 and 700 A below the cell surface, respectively.