(hī‵ă-lūr-ŏn'ĭ-dās )

An enzyme that disrupts or destroys the extracellular framework of body tissues. It is found in many animal tissues and can be synthesized for therapeutic use. In the testes and the acrosomes of spermatozoa, along with other acrosomal enzymes, it degrades the hyaluronic acid in the corona radiata, facilitating the entry of sperm. In malignant tumors, it participates in the invasion of cancer cells through the basement membranes of blood vessels. It is also a component of the venoms of several animals (including vipers, stonefish, and bees and wasps) and contributes to the tissue destruction that may follow bites or stings from these animals. Some infectious bacteria that invade fascial planes, e.g., Clostridia, release it as an exotoxin.

Uses: Synthetic hyaluronidase can be used to facilitate diffusion of injected local anesthetics, e.g., in cataract surgery.