Study of the release of cell wall degrading enzymes during adhesion of Chlamydomonas gametes

A quantitative assay for cell wall release in Chlamydomonas has been used to study the timing of release of cell wall degrading enzyme (lysin) during adhesion. Lysin activity, which shows a broad pH range and requires divalent cations, is released as a pulse within 1-2 min after mixing of mt^- and mt⁺ gametes. Thereafter, there is no further lysin release. Gametes of both mating types release the activity during aggregation with isolated gametic flagella of the opposite mating type, although mt⁺ gametes appear to release more lysin activity than mt^- gametes. Electrophoretic analysis of cell wall proteins before and after lysin degradation indicate that the major wall proteins are unchanged after wall breakdown.