Although the research efforts of the past decade have provided a molecular basis for many of the inborn errors of metabolism of the sphingolipidosis class, our knowledge of the enzymology of the catabolic, lysosomal glycolipid hydrolases of human tissues is limited. The enzymatic defect in Gaucher's disease was firmly established in 1965 by Brady, yet a thorough characterization of an extensively purified human beta-glucocerebrosidase has not been published. The broad objectives of the present research proposal are to purify and characterize beta-glucocerebrosidase(s) from human tissues and to extend our studies on the characterization of the lipid storage products which accumulate in the organs of individuals with Gaucher's disease. These studies will provide a sound basis for the development of enzyme-loaded red blood cells as a vehicle for enzyme-replacement therapy. The primary specific objectives of this proposal are: (1) to purify and characterize the soluble and membrane-bound isozymes of beta-glucocerebrosidase from human spleen, (2) to isolate, purify and characterize the ubiquitous glycoprotein component of Gaucher storage deposits and to investigate its effects on the soluble and membrane-bound isozymes of human spleen beta-glucocerebrosidase, (3) define conditions that will permit the efficient uptake of human beta-glucocerebrosidase by human red blood cells and to evaluate the use of these enzyme-charged red blood cells as a vehicle for enzyme-replacement therapy. The fruits of this research project can be applied to, and should accelerate progress in our understanding and treatment of a variety of human lysosomal storage diseases of the mucopolysaccharidosis and sphingolipidosis types.