Biochemical investigation to the reliability of the histochemical demonstration of microsomal arylsulphatase activity in cryostat sections

Summary Polyacrylamide gel-electrophoresis was performed with an extract from cultivated skin fibroblasts. Arylsulphatase activity is measured and visualised using the biochemical substrate dehydroepiandrosterone sulphate and the histochemical substrate 6-bromo-2-naphthyl sulphate respectively. The histochemical substrate was hydrolysed at Rf=0.49 and 0.58 while the biochemical substrate was hydrolysed only at 0.49. We conclude that two different microsomal arylsulphatases exist: a sulphatase able to hydrolyse steroid sulphatases (Rf=0.49) and one unable to hydrolyse steroid sulphatases (Rf=0.58). In consequence it is recommended to carry out an electrophoresis experiment after the histochemical investigation, in order to discriminate between these two types of sulphatase.