Studies on the Passage of α-Chymotrypsin across the Intestine. II. Enzymic Activity and Radioactive Macromolecule recovered in the Mesenteric Perfusate

Abstract

A perfusion with Krebs-Ringer solution containing dextran through the mesenteric vascular system was performed on rat to which ¹³¹I-labelled α-chymotrypsin was administered in the jejunum. This method sufficed for the purpose of eliminating various blood components, such as the inhibitors for the enzyme, which interfer with quantitative assay of a small amount of the enzyme absorbed. Using the method, the non-diffusible ¹³¹I-bound substance (s) and N-acetyl-L-tyrosine ethyl ester (ATEE)-hydrolyzing activity were found in the mesenteric perfusates of the rats, and the amount of the enzyme absorbed during 90 min was estimated to be about 0.6% of the infused dose. Furthermore, when the immunoreactivity with the antiserum against α-chymotrypsin was examined on the mesenteric perfusate, a precipitin band sharply indicating the enzyme was formed with the perfusate collected during the first 30 min after the administration. These results strongly suggest that small but significant amount of α-chymotrypsin is transmitted across the intestinal wall into the mesenteric vascular system as retaining its enzymic and immunochemical properties.