Tissue distribution, inhibition and activation of gelatinolytic activities in Atlantic cod ( Gadus morhua)

Gelatinolytic activities in fish tissues with properties like matrix metalloproteinases (MMPs) have been paid little attention. However, they have been proposed to participate in post mortem degradation during storage and the disintegration of pericellular connective tissue during spawning. In this paper the distribution of gelatinolytic activities in liver, heart, muscle, gill, and male and female gonad of Atlantic cod ( Gadus morhua) was studied by using gelatin SDS-PAGE, proteinase inhibitors, gelatin and lentil lectin Sepharose affinity chromatography. The amount of gelatin degrading enzymes varied from tissue to tissue. Most of the gelatin binding enzymes were found to be matrix metalloproteinases by adding galardin, a broad range MMP inhibitor, to the incubation buffer. A 72 kDa form of cod gelatin degrading enzyme had properties similar to human proMMP-2, as it could be activated by p-aminophenylmercuric acetate and trypsin. Like the human MMP-2 it did not bind to lentil lectin. An 83 kDa cod gelatin degrading enzyme had properties similar to the 92 kDa progelatinase B (proMMP-9). These properties were also similar to that of the 72 kDa form, except that the 83 kDa cod gelatinase was bound to lentil lectin, showing that it is a glycoprotein like MMP-9.