Structural identification and proteolytic effects of the hatching enzyme from starfish Asterias amurensis

Hatching enzyme (HE) is secreted from the blastula stage during fertilization and can cleave the egg membrane. The structural identification and proteolytic effects on the collagen and fibrinogen were investigated in this study. Approximate 20 kDa of Asn-linked oligosaccharides were attached to the HE. Five peptide fragments of the starfish HE were homogenous to those of the coat matrix protein of starfish Patiria pectinifera. Amino acids of the starfish HE consisted of mainly Leu (10.0%), Asp (12.5%), and Glu (12.8%). Collagenolytic and fibrinolytic activities of the starfish HE were weaker than those of collagenase and α-chymotrypsin. The degree values of hydrolysis for collagenase and α- chymotrypsin were significantly higher than those of HE in a dose- and time-dependent manner. The peptide mappings of the starfish HE on the collagenolysis (110.7, 84.7, and 20.8 kDa) and fibrinogenolysis (34, 30, and 29 kDa) were different from those of collagenase and α-chymotrypsin. Based on the proteolytic effects on the collagen and fibrinogen, the starfish hatching enzyme might have the potential application to remove the matrix composition in scar or keloid tissue.