Human Placental

AMAcetyl-,-he,osanindases A andUwere purifled to homogeneityfromhuman placenta. 1n the imt'al step of purication, thfe enzymes were adsorbed on concanavalin ASepharose 4B and etuted from, the column with a-methyl D-mannoside. Subsequent purification steps includedc DEAE-cellulose column chromn-atography, QAE-Seph%adex Ediethyl-(2-hydroxypropyl)aminoethyl-Sephadex] column chromatography1 Sephadex G-200 gel flItratiQn an4 preparative disc polyacxylamide-gel electrophoresis, followed by another QAE-Sephadex chromatography for the hexosaminidase A prepration, and IDEAEcellulose column chromatography, calcium phosphate gel chromatography, Sephadex G-200 gel filtration, QAE-Sephadex chrQmatography and CM-cellulose chromatography fQr the.hexosaminidase B preparation. The purifled preparations, particularly hexosaminidase A, had sinifscaxuy higher specific enzyme activities than previously reported. The preparationm moved on polyacrylamide-gel electrophoresis aj single protein bands, which also stained for enzyme activity. Sedimentation-equilibrium centrifugation indicated bomogeneous dispersion ofthe enzymes, and the molecular weight was estimated as about 11Q0000 for both enzymes. Complete amino acid and carbohydrate compositions of t,he two isoenzymes were determined, and, in contrast with prevouls suggestions, no si4lic acid was found in the enzymes.