Effect of leupeptin, a protease inhibitor, on dopa decarboxylase and protease activities in homogenates of submandibular salivary glands from young rats

Abstract

Dopa-decarboxylase activity was high at 2–3 weeks of age, low at 5–6 weeks, and very low in adult rats; protease activity increased with age. Trypsin-like proteases, which decrease dopa-decarboxylase activity, were detected in the gland and were inhibited by a protease inhibitor, leupeptin. High concentrations (20 mg/ml) of leupeptin increased dopa-decarboxylase activity in the glands of adult rats to the level found at 5–6 weeks of age. The low activity of dopa decarboxylase in adult gland may be due in part to endogenous proteases.