Purification and partial characterisation of a matrix metalloproteinase from ostrich skeletal muscle, and its activity during meat maturation.

The matrix metalloproteinases (MMPs) are a homologous family of zinc proteinases that are collectively capable of catabolising the various macromolecular components of the extracellular matrix including collagens. In this study an MMP was successfully isolated and purified from ostrich skeletal muscle using Toyopearl Super Q-650S, hydroxylapatite and zinc-chelate chromatographies. The purified molecule had a molecular weight of 55K and a total of 467 amino acid residues. Purified ostrich MMP showed a pH optimum of 7 and a temperature optimum of 45°C. The activity of purified ostrich MMP was shown to be inhibited by metal chelators (1,10 phenanthroline and EDTA) and partially inhibited by soy bean trypsin inhibitor. All the functional properties of ostrich MMP were compared to previously reported values for MMPs from other sources. The MMP activities in ostrich meat during a 21-day ageing period were determined and an overall increase in MMP activities was observed.