Activation of the matrix metalloproteinase inhibitor complex by a low molecular weight angiogenic factor.

Tissue inhibitor of matrix metalloproteinases is the major inhibitor of the collagenolytic enzymes and the inhibitory complex has been thought to be irreversible. In this paper we show that a low molecular weight non-protein endothelial cell stimulating angiogenic factor is able to reactivate the enzyme from the inhibitor complex and liberate free inhibitor. The importance of an angiogenic factor able to initiate limited degradation of extra-cellular matrix such that space is created for new capillary growth is discussed.