Gelatinase is a metallo-proteinase that acts specifically on denatured collagen. In human neutrophils, this enzyme is localized in small, morphologically still unidentified storage organelles that are resolved from the specific and the azurophil granules upon subcellular fractionation by differential sedimentation. When neutrophils isolated from freshly drawn blood are exposed to soluble stimuli such as N-formyl-methionyl-leucyl-phenylalanine, zymosan-activated serum, phorbol myristate acetate, or the calcium ionophore A 23187, or are induced to phagocytose opsonized zymosan, they rapidly release gelatinase in large amounts (30-70% of the cellular content in 10 min). When neutrophils from donor blood, which had been stored for 24 h at 4°C are used, extensive release even occurs without added stimuli by simply warming to 37°C.
Beatrice Dewald, Ursula Bretz, Marco Baggiolini