Characteristics of a 60K gelatinase involved in rat mammary gland involution

In order to study the role of matrix degrading enzymes in modulating cell matrix interaction, an understanding of the characteristics and regulation of their activity is useful. A number of matrix degrading metalloproteinases are involved in modulating the cell-ECM interactions during the involutory phase of mammary gland resulting in its remodelling. Zymographic studies showed that three types of gelatinases (60K, 68K and 130K) occur during the different phases of involution. The 60K gelatinase which appeared on the fifth day of involution has been purified by affinity chromatography over gelatin sepharose. Zymographic and radiolabelled substrate digestion studies at different pH and in presence of different cations showed that the activated form of this gelatinase is a Ca2+ dependent neutral matrix metalloproteinase capable of cleaving collagen I and collagen IV. Immunocytochemical studies showed that the enzyme is localised at pericellular/extracellular sites.