Abrupt induction of a membrane digestive enzyme by its intraintestinal substrate.

The regulation of amino-oligopeptidase (AOP), an intestinal brush border hydrolase essential for the surface digestion of peptide nutrients, was examined in rats in vivo. Short-term (30-minute) intraintestinal perfusion of a tetrapeptide substrate, Gly-Leu-Gly-Gly, or a synthetic substrate, leucyl-beta-naphthylamide, induced a doubling in the incorporation of [3H]leucine into the AOP in association with intracellular membranes. The subsequent conversion of AOP from nascent to mature enzyme and its membrane-associated transport to the brush border occurred at normal rates.