Transferase-deficiency galactosemia: Immunochemical studies of the Duarte and Los Angeles variants

Summary Rabbit antibodies to purified human placental galactose-l-phosphate uridyltransferase (EC 2.7.7.12) were used to establish immunologic cross-reactivity patterns for the enzyme in hemolysates, prepared from red cells of a normal individual, a homozygous Duarte variant, and a heterozygous Los Angeles variant. The antibody immunoprecipitated all three forms of the enzyme. The amount of antibody absorbed by each hemolysate was related to the different levels of activity, and examination of hemolysate/antibody reaction mixtures by starch gel electrophoresis revealed that the antibody quantitatively precipitated all of the isoenzyme forms that characterize these three genetic variants.This research was supported in part by a United States Public Health Service Grant, HD 06576, from the National Institute of Child Health and Human Development.