Red cell enzyme activity during blood storage and reactivation of phosphofructokinase

Activities of 21 red cell enzymes were measured in 15 units of CPD-Al anticoagulated blood before and after 35 days of storage. Paired t-tests revealed that five of the enzyme activities decreased significantly after 35 days of storage (P less than 0.05) while four increased significantly after storage (P less than 0.05). The most striking change was in phosphofructokinase (PFK), which decreased an average of 33% (P less than 0.005). Mean lactate dehydrogenase activity increased to 128% of its zero-day activity (P less than 0.005). Percent red cell survival, determined by reinfusion of a 51Cr-tagged aliquot of stored blood into the autologous donor, was highly correlated with 35-day ATP levels (r = 0.97; P less than 0.001). No significant relationships between two measures of red cell survival and any of the nine significantly altered enzymes were found. Studies of reactivation of PFK in hemolysates using 4 mM concentrations of numerous compounds indicate that the compounds or combinations of compounds used which reactivate PFK significantly all contain at least one high-energy phosphate group. These data suggest that loss of PFK activity during storage may be due to loss of organic phosphates. Whether the changes described have an important role in blood transfusion remains to be determined.