Hydrolysis of L-cystine-di-beta-naphthylamide and neurohypophyseal peptides by the plasma of the snake Bothrops jararaca.

1. Bothrops jararaca plasma or serum hydrolysed L-cystine-di-beta-naphthylamide (CNAse activity) at a degree comparable to that of plasma or serum in pregnant women. 2. In adult snakes, activity was less in males. It was not altered in pregnancy but increased after delivery, being higher at pH 6.4 (unspecific enzymes) than at pH 7.9 (true pregnant woman plasma oxytocinase). 3. Its optimum pH was 5.9, different from that of other known enzymes that hydrolyse the same substrate. 4. Bothrops jararaca plasma also hydrolysed vasopressin, oxytocin and vasotocin. 5. These hydrolysing activities were unexpected for an ovoviviparous reptile.