A modified method for chondrosulfatase assay.

In assaying for sulfatases it is possible to use several methods which have been devised for the determination of inorganic sulfate. As a test for chondrosulfatase, the micro benzidine method developed by Dodgson and Spencer (1) is usually employed. This method appears to be the most suitable because of its good sensitivity and absence of substrate interference, but its technique is complicated and demands a high degree of skill. On the other hand, the turbidimetric method of Dodgson and Price (2, 3), which has been used to determine inorganic sulfate liberated by acid hydrolysis, is simple and rapid, and has good reproducibility. However, when this method is used for chondrosulfatase assay, unraded substrate chondroitin sulfates interfere by forming a cloudy complex with the gelatin reagent in the assay system. In this study, the turbidimetric method was modified to permit determination of inorganic sulfate in the presence of chondroitin sulfate, and used to assay the chondrosulfatase of squid liver.