[Spontaneous solubilization of mcuosal peptide hydrolases in rat small intestine]

In vitro incubations of small intestine preparation lead to the spontaneous release of mucosal enzymes into the incubation medium, due to superficial dissolution and membrane lesions. One-hour anaerobic incubation of everted small intestine segments produces the liberation of from 13% (leucine arylamidase) to 30% (Gly-L-Pro-splitting peptide hydrolase) of the mucosal enzyme activities. Under the conditions of in vivo perfusion, the solubilization rates are from 50 to 80% lower than these values. The tendency to solubilization is only in part reduced to a significant extent by the saturation of the incubation medium with oxygen, but it does not reach the in vivo level. The detectability of membrane-bound and intracellular marker enzymes in the incubation medium permits no conclusions concerning the physiological localization of the released peptidases.