Isolation and characterization of hyaluronidase from cultures of chick embryo skin- and muscle-derived fibroblasts.

Primary and passaged cultures of chick embryo fibroblasts, prepared from 10-day embryonic skin and 12-day embryonic skeletal muscle, synthesize and secrete hyaluronidase at level comparable to the tissues of origin. The level of cell-associated hyaluronidase remains approximately constant during culture while the enzyme accumulates extracellularly such that within a 48-h incubation period, levels of hyaluronidase in the medium are 2 to 4 times higher than that found associated with the cell layer. The cultures continue to produce hyaluronidase at approximately the same rate and distribution through as many as nine passages. In addition to the chick fibroblasts, a variety of mammalian cells also produce hyaluronidase in culture. Both the cell- and medium-associated forms of the chick fibroblast hyaluronidase are endoglycosidases of estimated molecular weight of 62,000, which preferentially cleave hyaluronate substrate at an acidic pH optimum. Neither the cell-associated nor secreted hyaluronidase are enzymatically active at neutral pH.