The demonstration of multiple heat stable forms of N-acetyl-β-glucosaminidase in normal human serum

Abstract

1. 1. The hexosaminidase activity of normal human serum can be resolved into at least four components by DEAE-cellulose chromatography. 2. 2. The major part of the activity is in a form having similar properties to the hexosaminidase A of human tissues. 3. 3. Two new forms designated I 1 and I 2, intermediate in electrophoretic mobility between hexosaminidases A and B, have been separated. The I 2 form could not be distinguished from the P form present in sera from pregnant women. The concentration of this component in serum increased on storage. A serum sample from a diabetic patient also contained a high proportion of the I 2 form. 4. 4. There was a small proportion of hexosaminidase B in all sera examined but this component was only present in trace amounts in freshly drawn plasma. 5. 5. Application of the heat denaturation treatment commonly used in the detection of Tay-Sachs heterozygotes showed that the B and I forms had similar heat stability and that the heat labile A form can be converted to both I 1, I 2 and B forms by this procedure. 6. 6. The single heat-stable component found in the serum of a child with Tay-Sachs disease was an intermediate form and not hexosaminidase B.