Soluble arylsulfatases of human brain and some characteristics of the brain-specific arylsulfatase B_m

Abstract

The brain-specific arylsulfatase B_m (aryl-sulfate sulfohydrolase, EC 3.1.6.1) was demonstrable in human and monkey brain. Arylsulfatases A, B and B_m were separated employing DEAE-cellulose chromatography. There was a distinct difference in the proportion of the sulfatases in infant and adult human brain. Arylsulfatase B_m after concanavalin A-Sepharose chromatography showed the property of binding to Sephadex G-200 totally. Several dissociating agents failed to elute the enzyme from the bound form. Under similar conditions arylsulfatase A did not show any binding to Sephadex. On treatment with Escherichia coli alkaline phosphatase adult human brain arylsulfatase B_m but not arylsulfatase A was converted into a less acidic, presumably dephosphorylated form that did not bind to DEAE-cellulose. Monkey brain arylsulfatase B_m showed a similar susceptibility to E. coli phosphatase treatment. Inorganic phosphate and serine phosphate but not mannose 6-phosphate could inhibit this dephosphorylation. There were differences in the susceptibilities to alkaline phosphatase treatment of the arylsulfatase B_m from infant and adult human brain. Endogenous phosphatase also seemed to have a role on the phosphorylated state of arylsulfatase B_m.