Membrane-bound hemichrome in density-separated cohorts of normal (AA) and sickled (SS) cells.

The presence of bound heme pigment was compared in membranes of AA and SS cells. Spectophotometric study of membranes prepared by hypotonic lysis and washed free of hemoglobin revealed the presence of an irreversibly oxidized hemoglobin derivative, HCh. SS cell membranes contained significantly more HCh than did the AA cell membranes. When red cells were separated into cohorts of various density on a discontinuous density gradient of Stractan, washed membranes from the highest-density AA cells had significantly more HCh than did the remainder. In contrast, when density-separated SS cells were studied, no significant difference could be demonstrated in the HCh content of membranes from various cohorts.