These studies are designed to provide information regarding energy metabolism of the erythrocyte in relation to normal physiological processes and abnormal disease states. More precisely the broad objectives for these studies have been concerned with the generation of and utilization of energy in the erythrocyte, including the kinds of energy, means of generation and the processes requiring energy in order to maintain the erythrocyte. Previous studies in this laboratory have dealt with energy metabolism of normal cells under in vitro conditions similar to the in vivo environment for the erythrocyte. Future studies will deal with the definition of abnormal physical properties as they relate to the energy metabolism of the erythrocyte in both normal cells and disease states. Current studies are concerned with state of the intracellular hemoglobin in regard to the hydration of the protein or hemoglobin-water interactions. An abnormality of hemoglobin-water interaction has been defined in Hb CC disease in this laboratory. Preliminary studies of other disease state suggest that there are abnormalities in these areas and that they may be related to abnormalities of energy metabolism. The recent development of a more effective procedure for separating old and young erythrocytes has provided the opportunity to examine the normal aging process of erythrocytes for both normal and abnormal cells.