DIPEPTIDYL PEPTIDASE-IV AND AMINOPEPTIDASE IN BURN WOUND EXUDATES - IMPLICATIONS FOR WOUND-HEALING

Two catalytically active proteases, dipeptidyl peptidase IV (DP IV) an d aminopeptidase (AP), not previously reported as present in burn woun d exudates, have been identified by substrate specificity and suscepti bility to known enzyme inhibitors. The ratio of the two enzymes in exu dates is significantly different from the ratio in plasma collected fr om the same patient during the same time interval, suggesting that mea surement of exudate components may be more significant than plasma act ivities in evaluating local conditions in the wound. A number of biolo gically significant substances are DP IV substrates, and the list can be considerably extended by the sequential action of AP and DP IV. Som e polypeptides are converted to their biologically active form by DP I V action, while others are degraded to inactive forms. Either action g enerates X-Pro dipeptides, which have a demonstrably beneficial effect on wound healing. Although not resolved by molecular sizing or anion exchange chromatography, DP IV and AP in a burn wound exudate were pur ified by affinity chromatography.