Intracellular location of catalase-peroxidase hydroperoxidase I of Escherichia coli

Abstract
The catalase-peroxidase hydroperoxidase I of Escherichia coli has been confirmed to be located in the cytoplasm using two independent methods. Catalase activity was found predominantly (>95%) in the cytoplasmic fraction following spheroplast formation. The cytoplasmic enzyme glucose-6-phosphate dehydrogenase and the periplasmic enzyme alkaline phosphatase were used as controls. The second method of immunogold staining for the enzyme in situ revealed an even distribution of the enzyme across the cell.