Biochemical and physiological characterization of Sp-H, a hyaluronidase isolated from the venom of the scorpionfish Scorpaena plumieri

Hyaluronidases are ubiquitous enzymes in animal venoms, where they act as auxiliary toxins that facilitate the diffusion of other components by hydrolyzing hyaluronic acid (HA) in the extracellular matrix. In this study, we purified and biochemically characterized a hyaluronidase from the venom of the scorpionfish Scorpaena plumieri, a venomous fish from the Brazilian coast. The enzyme, designated Sp-H, was isolated with high purity through ammonium sulfate fractionation, size-exclusion chromatography, and anion-exchange chromatography. SDS-PAGE and MALDI-TOF MS revealed a monomeric glycoprotein with a molecular mass of ∼78 kDa. Sp-H exhibited maximal activity in pH range 5.8-6.5, was not significantly affected by NaCl concentrations up to 0.45 M, and retained activity for at least 30 days at 4 °C, -25 °C, or -80 °C. Peptide fragments identified by LC-MS/MS showed partial similarity (80-94 %) with hyaluronidases from stonefish and lionfish. Functionally, Sp-H enhanced the hemorrhagic activity of a snake venom metalloproteinase, indicating a diffusion-enhancing role consistent with that of hyaluronidases from other venomous animals. Moreover, anti-Sp-H IgG specifically recognized the enzyme and completely neutralized its activity in vitro. These findings identify Sp-H as a stable, immunogenic enzyme with biochemical properties comparable to other Scorpaenoid hyaluronidases. Although further studies are required to confirm its role in vivo, Sp-H represents a relevant component for understanding S. plumieri envenomation and a useful model for future studies on fish venom enzymes.