Purification and characterization of an endo-beta-galactosidase produced by Diplococcus pneumoniae.
An endo-beta-galactosidase acting on blood group A and B substances was found in the culture fluid of Diplococcus pneumoniae. The enzyme was purified 1000-fold, and its properties were studied in detail. The enzyme preparation, thus obtained, was practically free from various exoglycosidases, endo-beta-N-acetylglucosaminidase and proteases. The enzyme releases trisaccharides from blood group A and B active mucins purified from ovarian cyst fluid. The structures of the trisaccharides liberated from A and B active mucins were elucidated to be GalNAcalpha1 leads to 3(Fucalpha1 leads to 2)Gal and Galalpha1 leads to 3(Fucalpha1 leads to 2)Gal, respectively. The enzyme also hydrolyzes blood group A and B active oligosaccharides composed of type 2 chains, yielding the same products as in the case of ovarian cyst blood group substances. An H active mucin from ovarian cyst fluid, H active oligosaccharides, and A and B active oligosaccharides with type 1 chains were not hydrolyzed by the enzyme. Consequently, the enzyme catalyzes the following reaction, resulting in the degradation of blood type A and B determinants. (see article).
D000017:ABO Blood-Group System; D002413:Cations, Divalent; D002729:Chloromercuribenzoates / Q000494:pharmacology; D005696:Galactosidases / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008628:Mercury / Q000494:pharmacology; D009844:Oligosaccharides; D012834:Silver / Q000494:pharmacology; D013296:Streptococcus pneumoniae / Q000201:enzymology*; D013329:Structure-Activity Relationship
D000017:ABO Blood-Group System; D002413:Cations, Divalent; D002729:Chloromercuribenzoates; D009844:Oligosaccharides; D012834:Silver; D005696:Galactosidases; D008628:Mercury