Altered response of stored red cells to Ca2+ stress.

Short-term Ca2+ loading of erythrocytes was used as a test for probing membrane protein susceptibilities toward intrinsic enzymes in cells from fresh and from stored blood. The proteolytic response, affecting mainly glycophorin and band 3, could be elicited only in fresh cells, whereas the transglutaminase-mediated cross-linking reaction was evident both in fresh and stored cells. Loss of the proteolytic response might be an important sign of erythrocyte damage from blood bank storage.