THE HUMAN SPERM PROTEIN PH-20 HAS HYALURONIDASE ACTIVITY

The PH-20 protein present on the membrane of guinea pig sperm was char acterized using a monoclonal antibody [(1991) J. Cell Biol. 111, 2939- 2949]. We have isolated the cDNA encoding the human PH-20 protein from a testis library. This cDNA was expressed in RK 13 cells using a vacc inia virus expression system. Cells expressing the human PH-20 protein possess hyaluronidase activity. Treatment with PI-PLC releases the hy aluronidase into the the medium with a concomitant large increase in e nzymatic activity. These results demonstrate that the human PH-20 prot ein has hyaluronidase activity.