A New Hæmoprotein with a Unique Iron Porphyrin Prosthetic Group isolated from Human Erythrocytes

Abstract

HÆMOGLOBIN, 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 hæmoproteins in the erythrocyte. Catalase is one hæmoprotein which has been isolated from erythrocytes. A third hæmoprotein, spectrally similar to hæmoglobin but which has been reported to be functional in the methæmoglobin reductase system, has also been reported^1,2. It is the purpose of this communication to present observations on still another hæmoprotein 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.