Disaccharidase

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.^[1] For more online resources and references, see inborn error of metabolism.

References

1. 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.

Further reading

• 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. 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.