Collagenases from hepatopancreas and muscle of Litopenaeus vannamei: Purification, characterization and comparison of their behaviors in collagen degradation

Collagenases are responsible for collagen degradation, resulting in shrimp muscle softening after death. In this study, biochemical characteristics of collagenases purified from hepatopancreas (CPH) and muscle (CPM) of Litopenaeus vannamei were comparatively investigated. Changes of enzyme activity in shrimp hepatopancreas and muscle presented totally different tendencies, which decreased and increased respectively. Also, the key collagenases in different shrimp body parts were different. The CPH was identified as a highly metal-dependent serine proteinase, while the CPM was identified as a Ba²⁺-dependent metalloproteinase with a maximum activity at 50 °C and pH of 7.0. In terms of degradation behaviors, both CPH and CPM could hydrolyze type I collagen. However, because of diversified cleavage sites and higher efficiency, the CPM was able to degrade collagen more completely. Hence, these findings clarified the collagen degradation mechanism from a new perspective, providing theoretical basis for shrimp texture maintenance.