Properties and cDNA cloning of a hyaluronidase from the stonefish Synanceia verrucosa venom.

The venoms of two classes of fish, freshwater stingray (members of the genus Potamotrygon) and stonefish (members of the genus Synanceia), contain not only proteinaceous toxins but also hyaluronidases, which are considered as spreading factors that facilitate the tissue diffusion of toxins by degrading hyaluronan. So far, the freshwater stingray Potamotrygon motoro hyaluronidase and the stonefish Synanceia horrida hyaluronidase (SFHYA1) have been purified and characterized, although their spreading activity is still unclear. In this study, a 59 kDa hyaluronidase was partially purified from the stonefish Synanceia verrucosa and shown to be optimally active at pH 6.6, 37 °C and 0.15 M NaCl. Importantly, the S. verrucosa hyaluronidase enhanced the capillary permeability-increasing activity of the S. verrucosa toxin (neoverrucotoxin), providing evidence for its spreading activity. Furthermore, the primary structure of the S. verrucosa hyaluronidase was elucidated by cDNA cloning. The S. verrucosa hyaluronidase (463 amino acid residues) shares as high as 92% sequence identity with SFHYA1 but less than 50% with other hyaluronidases. Nevertheless, one catalytic residue and four substrate positioning residues, which constitute the active site of human hyaluronidases, are conserved in the S. verrucosa hyaluronidase.