Human neutrophil gelatinase is a collagenase type IV.

Secreted gelatinase from human neutrophils was purified as a 94 kDa polypeptide. Gelatinolytic and type IV collagenolytic activities of the purified protein were measured and compared. Immunoglobulins purified from antisera raised against gelatinase inhibited both the gelatinase and type IV collagenase activities. There was no cross-reaction in the inhibition with type I collagenase while the three metalloproteases were similarly inhibited by recombinant tissue inhibitor of metalloproteases. Purified gelatinase degraded denatured type I and native type IV collagens; there was no proteolysis of native type I collagen.