Purification and Partial Characterization of α-N-Acetylgalactosaminidase from Porcine Liver
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α-N-Acetylgalactosaminidase is an unusual lysosomal glycosidase in that no genetic abnormality involving this enzyme has been discovered. It was discovered many years ago, when Freudenberg and Eichel (1) found that extracts of the hepatopancreas from the snail Helix pomatia inactivated blood group A substance with the release of N-acetylhexosamine and galactose. Cell-free extracts of the flagellate Trichomonas foetus were also observed to contain activity that destroyed blood group A-active glycoprotein (2). Subsequent studies with partially purified preparations from these sources indicated that the loss of serological activity was accompanied by the concomitant liberation of terminal N-acetylgalactosamine (GalNAc) residues (3,4). Terminal GalNAc residues were also released from desialized sheep submaxillary mucin by enzyme fractions from various animal sources (5–7) and Clostridium perfringens (8).
KeywordsHydrolase Activity Artificial Substrate Porcine Liver Final Specific Activity Potassium Borate Buffer
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