Characterization of a recombinant matrix metalloproteinase-2 from sea cucumber (Stichopus japonicas) and its application to prepare bioactive collagen hydrolysate

摘要

Matrix metalloproteinase(s) (MMPs) are involved in collagen metabolism in sea cucumber. In the present study, a complete coding region of MMP-2 gene was cloned from the body wall of sea cucumber (Stichopus japonicas) and the open reading frame contained 1887 bp encoding 629 amino acid residues. The deduced amino acid sequence of MMP-2 contained a signal peptide, a propeptide domain, a catalytic domain with three repeats of fibronectin-type II region and a C-terminal hemopexin-like domain. According to the domain prediction of MMP-2, its catalytic domain was successfully expressed inEscherichia coli. After refolding, the purified recombinant MMP-2 (rMMP-2) exhibited a single band both on SDS-PAGE and zymography gel. The molecular mass of rMMP-2 was approximately 40 kDa. Circular dichroism spectrum revealed that the denaturation temperature of rMMP-2 was 56.80 ± 0.25 °C. Enzymatic characterization of rMMP-2 showed that it hydrolyzed gelatin most effectively at pH 8.5 and 40 °C, suggesting it is a slight alkaline proteinase. In addition, Ca2+was required for optimal gelatinolytic activity. The rMMP-2 degraded collagen effectively and the hydrolysate revealed scavenging activities on both 2, 2’-diphenyl-1-picrylhydrazyl free radical and hydrogen peroxide. These results indicated that rMMP-2 could potentially be applied for preparation of bioactive collagen hydrolysate.