Proteinase activity in Ascaris suum eggs, hatching fluid, and excretions-secretions.

Hatching fluid and the excretions and secretions (E.S.) of hatched larvae of Ascaris suum revealed proteinase activity when assayed by 2 different procedures employing collagen or casein as substrates. Both assays apparently detected similar levels of proteinase activity in hatching fluid and E.S. of hatched larvae. The Anson (casein substrate) assay worked best in 0.05 M phosphate buffer, pH 8.0. The Azocoll (collagen substrate) assay worked best in 0.05 M borate buffer at pH 8.8. Azocoll assays done at temperatures ranging from 25 to 65 C revealed maximal proteinase activity at 55 C. Analysis of hatching fluid from 18-, 21-, and 28-day-old embryos and of extracts from sonicated 0- to 28-day-old developmental stages showed that proteinase activity increased markedly 18 days after embryonation had begun. Prior to the 18th day of embryonation proteinase levels were relatively low.