Purification and properties of human kidney-cortex hexosaminidases A and B

Hexosaminidases (EC 3.2.1.30) A and B from human kidney cortex were purified to homogeneity by using concanavalin A affinity chromatography, ion-exchange chromatography and gel filtration. The yield of homogeneous isoenzymes improved approx. 20-fold, giving preparations of hexosaminidases A and B with specific activities of about 200 and 325 units/mg of protein respectively. The kinetic and structural properties of kidney hexosaminidase isoenzymes were studied and compared with the hexosaminidase isoenzymes from human placenta. The amino acid composition of hexosaminidase A was significantly different from that of hexosaminidase B. In the event of success in developing enzyme-replacement therapy for Tay-Sachs and Sandhoff's diseases, this modified procedure can furnish larger amounts of homogeneous isoenzymes.