EFFECT OF METAL BINDING ON HYDROGEN-TRITIUM EXCHANGE OF CONALBUMIN

1. 1. The rates of hydrogen-tritium exchange of chicken egg conalbumin and its metal complexes have been studied by the gel-filtration technique7 at pH 8, 4°. 2. 2. Iron-conalbumin retains approx. 50 more tritium atoms than does the apoprotein at all times during the course of exchange; both rapidly and slowly exchanging classes of hydrogen are shown to be affected by metal binding. 3. 3. Manganese- and copper-conalbumin also exchange more slowly than does the apoprotein, but these metals retard exchange less than does iron. 4. 4. The effect of iron on the hydrogen-tritium exchange of human serum transferrin is similar to that observed for conalbumin. 5. 5. These data suggest that the apo- and metalloproteins differ in conformation and that the structure of the latter is more compact. © 1969.