Ox adrenal esterases: their isoenzymes and subcellular localisation

Summary Esterase activity has been shown to exist in multiple forms in the ox adrenal cortical and medullary homogenates and subcellular fractions. Some esterase is adherent to membrane structures. The isoenzymes were resolved into carboxylesterases, arylesterases, acetylesterases and cholinesterases. The distribution of the enzyme groups differed slightly between cortex and medulla.The distribution of specific activity of esterase in ox adrenal medullary and cortical fractions was also investigated. The highest activity was found with the microsomes but there was some activity with the other fractions. Medullary lysosomes were separated by gradient centrifugation and shown to contain esterase activity. The results were discussed in relation to histochemical findings at the light and electron microscopic levels.