Granules fuse in reverse order 3-2-1. Secondary granules contain NADPH oxidase - need these to fuse first to generate H2O2 for MPO to convert and make hypochlorite ion OCl-. Both primary and secondary granules contain lysozyme. Tertiary granules contain cathepsin (proteases), gelatinase and collagenase {{ :general_pathology:acute:neutrophil_granules.png |}}