Disaccharidase - Misplaced Pages

Enzymes that break down disaccharides into monosaccharides

Disaccharidases are glycoside hydrolases, enzymes that break down certain types of sugars called disaccharides into simpler sugars called monosaccharides. In the human body, disaccharidases are made mostly in an area of the small intestine's wall called the brush border, making them members of the group of "brush border enzymes".

A genetic defect in one of these enzymes will cause a disaccharide intolerance, such as lactose intolerance or sucrose intolerance.

Examples of disaccharidases

Lactase (breaks down lactose into glucose and galactose)
Maltase (breaks down maltose into 2 glucoses)
Sucrase (breaks down sucrose into glucose and fructose)
Trehalase (breaks down trehalose into 2 glucoses)

For a thorough scientific overview of small-intestinal disaccharidases, one can consult chapter 75 of OMMBID. For more online resources and references, see inborn error of metabolism.

References

Charles Scriver, Beaudet, A.L., Valle, D., Sly, W.S., Vogelstein, B., Childs, B., Kinzler, K.W. (Accessed 2007). The Online Metabolic and Molecular Bases of Inherited Disease. New York: McGraw-Hill. - Summaries of 255 chapters, full text through many universities. There is also the OMMBID blog Archived 2007-02-06 at the Wayback Machine.

Poley, J. R.; Bhatia, M.; Welsh, J. D. (1978). "Disaccharidase deficiency in infants with cow's milk protein intolerance. Response to treatment". Digestion. 17 (2): 97–107. doi:10.1159/000198100. PMID 627328.
Neale, G (1971). "Disaccharidase deficiencies". J Clin Pathol Suppl (R Coll Pathol). 5: 22–28. doi:10.1136/jcp.s3-5.1.22. PMC 1176256.
Laws, J. W.; Neale, G. (1966). "Radiological diagnosis of disaccharidase deficiency". Lancet. 2 (7455): 139–143. doi:10.1016/S0140-6736(66)92424-X. PMID 4161630.
Laws, J. W.; Spencer, J.; Neale, G. (1967). "Radiology in the diagnosis of disaccharidase deficiency". The British Journal of Radiology. 40 (476): 594–603. doi:10.1259/0007-1285-40-476-594. PMID 4952296.

Hydrolase: sugar hydrolases (EC 3.2)

3.2.1: Glycoside hydrolases

Disaccharidase	Sucrase/Sucrase-isomaltase/Invertase Maltase Trehalase Lactase
Glucosidases	Cellulase Alpha-glucosidase Acid Neutral AB Neutral C Beta-glucosidase cytosolic Debranching enzyme
Other	Amylase Alpha-amylase Chitinase Lysozyme Neuraminidase NEU1 NEU2 NEU3 NEU4 Bacterial neuraminidase Viral neuraminidase Galactosidases Alpha Beta alpha-Mannosidase Glucuronidase Klotho Hyaluronidase Pullulanase Glucosylceramidase lysosomal non-lysosomal Galactosylceramidase Alpha-N-acetylgalactosaminidase NAGA Alpha-N-acetylglucosaminidase Fucosidase Hexosaminidase HEXA HEXB Iduronidase Maltase-glucoamylase Heparanase HPSE2

3.2.2: Hydrolysing
N-Glycosyl compounds

DNA glycosylases: Oxoguanine glycosylase

v t e Enzymes
Activity	Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Diffusion-limited enzyme Cofactor Enzyme catalysis
Regulation	Allosteric regulation Cooperativity Enzyme inhibitor Enzyme activator
Classification	EC number Enzyme superfamily Enzyme family List of enzymes
Kinetics	Enzyme kinetics Eadie–Hofstee diagram Hanes–Woolf plot Lineweaver–Burk plot Michaelis–Menten kinetics
Types	EC1 Oxidoreductases (list) EC2 Transferases (list) EC3 Hydrolases (list) EC4 Lyases (list) EC5 Isomerases (list) EC6 Ligases (list) EC7 Translocases (list)

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Examples of disaccharidases

References

Further reading