Enzyme-linked Immunosorbent Assay for the Ganglioside GM2-Activator Protein. Screening of Normal Human Tissues and Body Fluids, of Tissues of GM2Gangliosidosis, and for Its Subcellular Localization

Abstract
An enzyme-linked immunosorbent assay was developed for the quantitation of the human activator protein for ganglioside GM2 degradation by .beta.-N-acetyl-D-hexosaminidase A. With this assay, various tissues and body fluids of normal subjects and of patients with variant forms of GM2 gangliosidosis were screened for the GM2-activator content. The highest content of this protein was found in kidney. Tissues from patients with variant AB of infantile GM2 gangliosidosis contained only low levels (up to 5% of that of normal controls) of cross-reacting material. On subcellular fractionation of normal human skin fibroblasts, the activator was found to codistribute with the lysosomal marker enzyme .beta.-hexosaminidase.