Relation of hemoglobin to the red cell membrane

Despite the accumulation of biochemical and physiological knowledge of hemoglobin, little is cer-tain about its physical state in the native red blood cell. Perutz and Mitchison ( 1) indicate that the pigment is almost surely not in the crystalline state except for sickle-hemoglobin in the reduced form. A separate aspect of the problem is the relation of hemoglobin to the cell membrane. The prevail-ing view is that of the respiratory physiologists who hold that the exchange of blood gases involves no chemical event in the membrane (2). Accord-ingly, hemoglobin is excluded from it. Drabkin has estimated that not more than about 2 per cent of the total pigment could be "anchored at the surface of the red cell " (3), while Hoffman has recently concluded emphatically that the notion that there may be structurally fixed hemoglobin must be abandoned (4). Yet, many investigators have been struck by the difficulty encountered in trying to free red cell stromata entirely from he-moglobin. For example, Zittle, Della Monica and Custer, in preparing red cell acetylcholinesterase, noted the stromata contained "considerable hemo-globin in spite of the long period of washing" (5). Ponder, in a recent review (6), favors the idea that some of the pigment is associated with the membrane. His view is based in part on mi-croscopic observations that could bear other inter-pretations and afford no quantitative data, and in part on the finding that "ghosts " may contain a greater concentration of hemoglobin than the sur-rounding lytic solution, "provided that the amount of water used for hemolyzing the cells is relatively small. " Unfortunately, with only small amounts of water lysis is likely to be incomplete, and it is accordingly improbable that there is free diffusio