Separation and analysis of arylsulfatase isoenzymes in body fluids of man.

Soluble arylsulfatase (EC 3.1.6.1) is present in the body fluids of man in the form of two isoenzymes, arylsulfatase A and B, which reportedly are useful biochemical markers for certain types of malignancy. However, rapid assay of the individual isoenzymes is extremely difficult; procedures based on differential inhibition or activation of the isoenzymes in a mixture yield only semiquantitative results. A feature of these isoenzymes is their inhibition by some common anions (notably phosphate) at physiologic concentrations. The isoenzymes can be separated by anion-exchange chromatography, the B isoenzyme being eluted in the void volume and the A isoenzyme and the anionic inhibitors retarded. Lead is used to sequester phosphate, enabling measurement of A in the salt-eluted fraction. Using this technique, we have found significant elevations of B in the sera of patients with colorectal cancer. The potential of rapid, chromatographic separation coupled with continuous monitoring for arylsulfatase activity is discussed.