Action of endo-alpha-N-acetylgalactosaminidase from Alcaligenes sp. on amino acid-O-glycans: comparison with the enzyme from Diplococcus pneumoniae.
Endo-alpha-N-acetylgalactosaminidase from Alcaligenes sp. released the disaccharide, Gal beta 1----3GalNAc, from both dansylated serine-GalNAc-Gal and threonine-GalNAc-Gal, and showed higher activity on the former than the latter. The Km values were 0.17 mM and 1.43 mM with DNS-Ser-GalNAc-Gal and DNS-Thr-GalNAc-Gal, respectively. The optimum pHs were found to be 4.5-7.5 and 4.5-6.0 on DNS-Ser-GalNAc-Gal and DNS-Thr-GalNAc-Gal, respectively. On the contrary, the enzyme from Diplococcus pneumoniae had low activity to release the disaccharide from the amino acid-O-glycans. The possibility that the same O-glycoside but linked to different aglycon amino acids may play a different biological role in glycoproteins is discussed.
Fan
J Q
JQ
Department of Food Science and Technology, Kyoto University, Japan.
Yamamoto
K
K
Matsumoto
Y
Y
Hirabayashi
Y
Y
Kumagai
H
H
Tochikura
T
T
D000421:Alcaligenes / Q000201:enzymology*; D000596:Amino Acids; D002240:Carbohydrate Sequence; D006023:Glycoproteins; D006027:Glycosides; D006596:Hexosaminidases / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D013296:Streptococcus pneumoniae / Q000201:enzymology*; D013379:Substrate Specificity; D048809:alpha-N-Acetylgalactosaminidase
D000596:Amino Acids; D006023:Glycoproteins; D006027:Glycosides; D006596:Hexosaminidases; D048809:alpha-N-Acetylgalactosaminidase