Diffusion of Alkaline Phosphatase to Characteristic Intracytoplasmic Sites of Activity

Abstract

WHILE using superimposed frozen-dried sections of rat kidney for the study of diffusion phenomena¹ in the Gomori²–Takamatsu³ technique for alkaline phosphatase, it was observed that faint staining of the brush border regions occurred in the underlying inactive section in very occasional tubules. This result was obtained after moderately prolonged incubation, even when inactivation of the underlying section was effected by heat. The appearances suggested that the enzyme itself, enzyme activator or phosphate ion was diffusing into the underlying section, and prompted further experiments to demonstrate enzyme diffusion to characteristic positions in the cell⁴.