Hyaluronidases in tissue invasion.

Hyaluronidases are broadly distributed enzymes with varying substrate specificities, a wide range of pH optima, and different catalytic mechanisms. They may be used by organisms to invade one another. Hyaluronidases have also been invoked as mechanisms for tumor invasion and metastatic spread. In this review, we will concentrate more on the different kinds of hyaluronidases involved in tissue invasion other than cancer metastasis, present some of the rapidly accumulating new data, and address the paradox that both hyaluronidase as well as its hyaluronan substrate are associated with invasion.