Ascorbic acid-2-sulfate sulfhohydrolase activity of human arylsulfatase A

Pure human arylsulfatase A (EC 3.1.6.1) was found to hydrolyze ascorbic acid 2-sulfate to ascorbic acid and inorganic sulfate at rates from 200 to 2000 mumol/mg per h depending on the method of assay. This rate was lower than that observed with the synthetic substrate 4-nitrocatechol sulfate, but higher than that seen with the physiological substrate cerebroside sulfate. Extracts of cultured fibroblasts from normal subjects were also shown to hydrolyze ascorbic acid 2-sulfate; extracts of fibroblasts from patients with metachromatic leukodystrophy, known to be deficient in arylsulfatase A, did not. Similarly, hydrolysis of ascorbic acid 2-sulfate was not observed when a partially purified preparation of human arylsulfatase B was tested under a variety of conditions. Thus, in the human, arylsulfatase A appears to be the major, if not the only, ascorbic acid-2-sulfate sulfohydrolase.