A cell wall lytic enzyme of Chlamydomonas reinhardtii has been purified and identified as a single glycopolypeptide subunit of 62 kDa by SDS—polyacrylamide gel electrophoresis. It is released into culture medium by mating gametes as a large aggregate of subunits. The purified enzyme shows a pH optimum at about 7.5 and 35°C. Metal ion chelators and SH-blocking agents inhibit the activity. The activity is also diminished by α2-macroglobulin.