“…The cytoplasmic localization of these enzymes in human tracheobronchial epithelial cells is in accord with the results obtained for the same enzymes in rat-liver cells by the technique of differential centrifuging of cell homogenates. Although a good correlation between RNA content of the cells and enzymes which are localized in the endoplasmic reticulum might have been expected, a similar high degree of correlation was seen with acid phosphatase and arylsulphatases A plus B, which are found in the lysozymes (Viala & Gianetto, 1955;Dodgson, Spencer & Thomas, 1954), and f,-glucuronidase, which is of mixed mitochondrialysozyme localization (de Duve, Pressman, Gianetto, Wattiaux & Appelmans, 1955). The correla--tion of RNA content with the activities of these various enzymes may indicate some direct relationship, or, both the RNA content and the enzyme activities may simply be reflexions of the variation in cytoplasmic size of the cell (Fig.…”