Multiple components of beta-N-acetylhexosaminidase from equine kidney. Their action on glycolipids and allied oligosaccharides.

Abstract

β-N-Acetylhexosaminidase [EC 3.2.1.52] extracted from equine kidney had three components, acidic A, basic B, and a third one A'. These three components were separated by a combination of DEAE- and CM-cellulose column chromatography. Isoelectric points were: A, 6.07; A', 6.25; B, 8.20. Component A was heat labile. Component B was relatively stable against heat treatment but lost activity rapidly above 55°C. Component A' was very heat stable, and retained 75% of its activity after 30 min at 60°C. The molecular weights of A, A', and B were 125,000, 250,000, and 125,000 daltons, respectively. The Michaelis constants against phenyl β-N-acetylgalactosaminide were A: 0.147mM, A': 0.102mM, and B: 0.043mM, and those against p-nitrophenyl β-N-acetylgalactosaminide was A: 0.571 mM, A': 0.246 mM, and B: 0.086 mM. Oligosaccharide obtained from ganglioside GM2 was hydrolyzed only by A and A', not by B, and those from asialo GM2 and Globoside I were hydrolyzed by all three components. Component A preparation free from sialidase [EC 3.2.1.18] was not converted to B by sialidase from Cl. perfringens.