The proposed investigation will deal with a detailed examination of the factors which control the depolymerization of hemoglobin S gelation and desickling of red blood cells by the alkylureas and other related reagents that are to be synthesized as a part of the study. Related denaturation and hemoglobin dissociation studies by spectroscopic, spectropolarimetric, and molecular weight methods, will be carried out in order to determine the effects of the reagents synthesized and studied on the secondary and quaternary structure of hemoglobin. The understanding of the controlling factors that govern the inhibition of the polymerization of sickle-cell hemoglobin is of great potential value for both the understanding of the molecular basis of the sickling disease and the rational design of therapeutic reagents that are to be used eventually for the treatment of sickle cell anemia. Laser light scattering measurements on hemoglobulin S and A solutions related to the nature of the pregelation state of the protein and the mode of gel-formation and inhibition will also be made concerning this problem.