A simplified assay method for galactosyl ceramide beta-galactosidase.

In a previously described method for determining the activity of cerebroside galactosidase, the enzyme preparation was incubated with an emulsion of cerebroside which had been labeled in the galactose moiety. The liberated galactose was separated from the emulsion by liquid-liquid partitioning, but the presence of detergent necessitated the use of careful agitation and a backwash in order to reduce the contamination of the aqueous layer with excess emulsified substrate. This problem is eliminated by adding a large amount of lipid to reduce the emulsifying power of the detergent. It may be that other lipid hydrolase assays, based on the same principle, would benefit by this approach. Some additional improvements in the assay system are described.