Characterization of lizard venom hyaluronidase and evidence for its action as a spreading factor

Hyaluronidase was isolated from the lizard (Heloderma horridum horridum) crude venom. The chemical properties were characterized and compared to the same enzyme from other sources. The enzyme was found to be a single polypeptide chain with a molecular weight of 63,000 daltons. It possesses an isoelectric point and pH optimum of 5.0, and was observed to be extremely temperature sensitive. The role of hyaluronidase as a spreading factor which serves to aid in the diffusion of toxins has been suspected for a long time; yet no experimental proof has been offered until now. It was shown that hyaluronidase promotes the spread of the hemorrhagic area in mice when injected with hemorrhagic toxin. Thus experimental evidence is supplied for the first time that the enzyme plays a role as a "spreading factor" in the toxic action of venom.