During phagocytosis neutrophils from 8 patients with chronic granulomatous disease released 2-3 times more activity of lysozyme and beta-glucuronidase than did normal neutrophils. This difference was caused by the partial inactivation of these enzymes by normal neutrophils. The inactivation of granule enzymes depends on oxidative products and takes place mainly in the phagolysosomes. Myeloperoxidase is involved in this phenomenon.