A new haemoprotein with a unique iron porphyrin prosthetic group isolated from human erythrocytes.

Abstract

HAEMOGLOBIN, comprising more than 95 per cent of the protein of the red cell, is the major protein in the mature human erythrocyte. The extremely high concentration of this compound in the red cell renders very difficult the identification of other haemoproteins in the erythrocyte. Catalase is one haemoprotein which has been isolated from erythrocytes. A third haemoprotein, spectrally similar to haemoglobin but which has been reported to be functional in the methaemoglobin reductase system, has also been reported1,2. It is the purpose of this communication to present observations on still another haemoprotein which has been isolated from normal human erythrocytes. This compound is particularly noteworthy since its prosthetic group appvears to be different from any previously reported naturally occurring iron porphyrin.