THE EFFECT OF PRONASE ON VITAMIN B_<12> ABSORPTION

Abstract

The effect of Pronase, an enzyme preparation of Streptomyces, on vitamin B_<12> absorption from rat intestinal loops was studied in comparison with that of intrinsic factor. It has been found that Pronase does not bind B_<12> in vitro as does intrinsic factor, and that its effect is quite different from that of intrinsic factor. Absorption of B_<12> under the influence of Pronase was much slower than that effected by intrinsic factor, and Pronase had no effects on the absorption of radioactive iodide, chromate or thiamine (-^<35>S), suggesting that Pronase does not increase permeability of the mucosa but specifically enhances absorption of B_<12>. It has also been found that in the loop, B_<12> is converted within one hour to a state where intrinsic factor can no longer act on B_<12>, but Pronase does increase absorption of such B_<12>, and that Pronase does not destroy the so-called"mucosal receptor."