Structural evidences for chelation and Schiff's base formation in amino acid transfer into cells.

The present communication considers some findings which appear to implicate chelation in the amino acid concentration process. The inquiry grows out of the finding that pyridoxal stimulates concentration of amino acids by Ehrlich ascites tumor cells, and that cells from vitamin Be-deficient mice show a deficient concentrating ability (4, 5). Metal chelation is known to be involved in the catalytic functioning of pyridoxal in nonenzymatic systems (6, 7) and at least in some enzymatic systems (8). Metal-amino acid-pyridoxal complexes similar to those shown in Fig. 1 are believed to be involved.