The localization of mutarotase in rat kidney.

The localization of mutarotase in rat kidney was investigated by fluorescein-labelled and peroxidase-labelled antibody techniques, and by method of isolation of the nuclei and cytoplasm in non-aqueous solvents. In these immunohistochemical studies, mutarotase was almost exclusively recognized in the nuclei of epithelial cells of renal tubules and glomeruli in rat. The specific activity of mutarotase was found to be 1.5 times higher in the nuclei (122 units/g dry wt) than that in the cytoplasm (80 units/g dry wt) isolated with non-aqueous solvents. These results suggest that mutarotase may be involved in the metabolism of D-glucose in nuclei.