Enzymes
| UniProtKB help_outline | 145 proteins |
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- Name help_outline β-D-glucosyl-(1↔1ʼ)-N-hexadecanoylsphinganine Identifier CHEBI:84782 Charge 0 Formula C40H79NO8 InChIKeyhelp_outline BLGKYYVFGMKTEZ-UKDORTLVSA-N SMILEShelp_outline CCCCCCCCCCCCCCC[C@@H](O)[C@H](CO[C@@H]1O[C@H](CO)[C@@H](O)[C@H](O)[C@H]1O)NC(=O)CCCCCCCCCCCCCCC 2D coordinates Mol file for the small molecule Search links Involved in 1 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H2O Identifier CHEBI:15377 (CAS: 7732-18-5) help_outline Charge 0 Formula H2O InChIKeyhelp_outline XLYOFNOQVPJJNP-UHFFFAOYSA-N SMILEShelp_outline [H]O[H] 2D coordinates Mol file for the small molecule Search links Involved in 6,485 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline N-hexadecanoylsphinganine Identifier CHEBI:67042 Charge 0 Formula C34H69NO3 InChIKeyhelp_outline GCGTXOVNNFGTPQ-JHOUSYSJSA-N SMILEShelp_outline CCCCCCCCCCCCCCC[C@@H](O)[C@H](CO)NC(=O)CCCCCCCCCCCCCCC 2D coordinates Mol file for the small molecule Search links Involved in 6 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline β-D-glucose Identifier CHEBI:15903 (CAS: 492-61-5) help_outline Charge 0 Formula C6H12O6 InChIKeyhelp_outline WQZGKKKJIJFFOK-VFUOTHLCSA-N SMILEShelp_outline OC[C@H]1O[C@@H](O)[C@H](O)[C@@H](O)[C@@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 39 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:69711 | RHEA:69712 | RHEA:69713 | RHEA:69714 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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Differential mechanism-based labeling and unequivocal activity assignment of the two active sites of intestinal lactase/phlorizin hydrolase.
Arribas J.C., Herrero A.G., Martin-Lomas M., Canada F.J., He S., Withers S.G.
Milk lactose is hydrolysed to galactose and glucose in the small intestine of mammals by the lactase/phlorizin hydrolase complex (LPH; EC 3.2.1.108/62). The two enzymatic activities, lactase and phlorizin hydrolase, are located in the same polypeptide chain. According to sequence homology, mature ... >> More
Milk lactose is hydrolysed to galactose and glucose in the small intestine of mammals by the lactase/phlorizin hydrolase complex (LPH; EC 3.2.1.108/62). The two enzymatic activities, lactase and phlorizin hydrolase, are located in the same polypeptide chain. According to sequence homology, mature LPH contains two different regions (III and IV), each of them homologous to family 1 glycosidases and each with a putative active site. There has been some discrepancy with regard to the assignment of enzymatic activity to the two active sites. Here we show differential reactivity of the two active sites with mechanism-based glycosidase inhibitors. When LPH is treated with 2',4'-dinitrophenyl 2-deoxy-2-fluoro-beta-D-glucopyranoside (1) and 2', 4'-dinitrophenyl-2-deoxy-2-fluoro-beta-D-galactopyranoside (2), known mechanism-based inhibitors of glycosidases, it is observed that compound 1 preferentially inactivates the phlorizin hydrolase activity whereas compound 2 is selective for the lactase active site. On the other hand, glycals (D-glucal and D-galactal) competitively inhibit lactase activity but not phlorizin hydrolase activity. This allows labeling of the phlorizin site with compound 1 by protection with a glycal. By differential labeling of each active site using 1 and 2 followed by proteolysis and MS analysis of the labeled fragments, we confirm that the phlorizin hydrolysis occurs mainly at the active site located at region III of LPH and that the active site located at region IV is responsible for the lactase activity. This assignment is coincident with that proposed from the results of recent active-site mutagenesis studies [Zecca, L., Mesonero, J.E., Stutz, A., Poiree, J.C., Giudicelli, J., Cursio, R., Gloor, S.M. & Semenza, G. (1998) FEBS Lett. 435, 225-228] and opposite to that based on data from early affinity labeling with conduritol B epoxide [Wacker, W., Keller, P., Falchetto, R., Legler, G. & Semenza, G. (1992) J. Biol. Chem. 267, 18744-18752]. << Less
Eur J Biochem 267:6996-7005(2000) [PubMed] [EuropePMC]
This publication is cited by 15 other entries.
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On the identity between the small intestinal enzymes phlorizin hydrolase and glycosylceramidase.
Leese H.J., Semenza G.
J. Biol. Chem. 248:8170-8173(1973) [PubMed] [EuropePMC]
This publication is cited by 6 other entries.
Comments
Published in: "The configurations at the anomeric carbon of the reaction products of some digestive carbohydrases." Semenza, G., Curtius, H.-C., Raunhardt, O. & Muller, M. (1969) Carbohydr. Res.10, 417-428.