Influence of pyridoxine, pyridoxal phosphate, deoxypyridoxine, and 2,4-dinitrophenol on methionine absoption.

It has been demonstrated by studies in vitro and in vivo that two absorptive processes are involved in the intestinal absorption of amino acids. It is also apparent that the vitamins of the Bggroup play a role in the “active” process of cellular uptake of amino acids (2) and that deoxpyridoxine (3) and 2,4-dinitrophenol (3,4), have an inhibitory effect upon active absorptive processes. We are presenting evidence that pyridoxal phosphate alleviates deoxypyridoxineand 2,4-dinitrophenol-induced inhibition of methionine absorption, and that the inhibitory block is linked to the phosphorylation of the vitamin cofactor. These studies extend our investigations on methionine absorption (5) and lend further support to the hypothesis that the Be-vitamins are involved actively in the absorptive process in the steady state.