Effect of sulphydryl inhibition on the uptake of transferrin-bound iron by reticulocytes.

Iron transferrin, the highly stable carrier of plasma iron, may be dissociated, under physiological conditions, by sodium thioglycollate, a reaction which involves the formation of iron thioglycollate complexes. This suggested that sulphydryl radicals, which are the active groups in thioglycollate and related compounds, may play a part in the uptake of iron by immature red cells from iron transferrin. If this were so, it could be predicted that the sulphydryl inhibitor, p-hydroxymercuribenzoate, would depress the uptake of iron by reticulocytes. It is demonstrated here that inhibition of uptake of transferrin-bound iron by reticulocytes, which have been exposed to micromolar concentration of p-hydroxymercuribenzoate, is virtually complete. It is suggested that sulphydryl-containing compounds are intimately involved in the process of iron uptake by immature red cells.