The Enzyme Database

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Accepted name: glycosylceramidase
Reaction: (1) a β-D-glucosyl-N-acylsphingosine + H2O = a ceramide + β-D-glucose
(2) a β-D-galactosyl-N-acylsphingosine + H2O = a ceramide + β-D-galactose
(3) a flavonoid-O-β-D-glucoside + H2O = a flavonoid + β-D-glucose
For diagram of phloretin biosynthesis, click here and for diagram of glycolipid biosynthesis, click here
Glossary: a ceramide = an N-acylsphingosine
Other name(s): phlorizin hydrolase; phloretin-glucosidase; glycosyl ceramide glycosylhydrolase; cerebrosidase; phloridzin β-glucosidase; lactase-phlorizin hydrolase; phloridzin glucosidase; LPH (gene name); LCT (gene name); glycosyl-N-acylsphingosine glycohydrolase
Systematic name: β-D-glucosyl-N-acylsphingosine glycohydrolase (configuration-retaining)
Comments: The enzyme, found in the intestinal mucosa, hydrolyses β-D-glucosyl and β-D-galactosyl residues from a very broad range of substrates using a retaining mechanism. Characterized substrates include glucosyl- and galactosyl-ceramides [3], O3-, O4′ and O7-glucosylated flavonoids [6], and the 2′-O-glucosylated dihydrochalcone phlorizin [1]. The enzyme includes two glycosyl hydrolase domains, both belonging to the GH1 family. While one domain is responsible for the activity described here, the other catalyses the reaction of EC, lactase [4,5]. cf. EC, glucosylceramidase and EC, galactosylceramidase.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 9033-10-7
1.  Malathi, P. and Crane, R.K. Phlorizin hydrolase: a β-glucosidase of hamster intestinal brush border membrane. Biochim. Biophys. Acta 173 (1969) 245–256. [DOI] [PMID: 5774775]
2.  Lorenz-Meyer, H., Blum, A.L., Haemmerli, H.P. and Semenza, G. A second enzyme defect in acquired lactase deficiency: lack of small-intestinal phlorizin-hydrolase. Eur. J. Clin. Invest. 2 (1972) 326–331. [DOI] [PMID: 5082068]
3.  Leese, H.J. and Semenza, G. On the identity between the small intestinal enzymes phlorizin hydrolase and glycosylceramidase. J. Biol. Chem. 248 (1973) 8170–8173. [DOI] [PMID: 4752949]
4.  Zecca, L., Mesonero, J.E., Stutz, A., Poiree, J.C., Giudicelli, J., Cursio, R., Gloor, S.M. and Semenza, G. Intestinal lactase-phlorizin hydrolase (LPH): the two catalytic sites; the role of the pancreas in pro-LPH maturation. FEBS Lett. 435 (1998) 225–228. [DOI] [PMID: 9762914]
5.  Arribas, J.C., Herrero, A.G., Martin-Lomas, M., Canada, F.J., He, S. and Withers, S.G. Differential mechanism-based labeling and unequivocal activity assignment of the two active sites of intestinal lactase/phlorizin hydrolase. Eur. J. Biochem. 267 (2000) 6996–7005. [DOI] [PMID: 11106409]
6.  Nemeth, K., Plumb, G.W., Berrin, J.G., Juge, N., Jacob, R., Naim, H.Y., Williamson, G., Swallow, D.M. and Kroon, P.A. Deglycosylation by small intestinal epithelial cell β-glucosidases is a critical step in the absorption and metabolism of dietary flavonoid glycosides in humans. Eur J Nutr 42 (2003) 29–42. [DOI] [PMID: 12594539]
[EC created 1972, modified 1976, modified 2022]

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