View source for Sucrase

{{Short description|Enzyme}}
'''Sucrases''' are digestive [[enzyme|enzymes]] that [[catalysis|catalyze]] the [[hydrolysis]] of [[sucrose]] to its component monosaccharides, [[fructose]] and [[glucose]]. One form, [[sucrase-isomaltase]], is secreted in the [[small intestine]] on the [[brush border]].<ref>{{Cite book|title=Principles of Anatomy & Physiology 14th edition|last=Tortora|first=Gerard|publisher=Wiley|year=2014|isbn=978-1-118-34500-9|location=USA|pages=[https://archive.org/details/principlesofanat0000tort/page/924 924]|url=https://archive.org/details/principlesofanat0000tort/page/924}}</ref> The enzyme [[invertase]], which occurs more commonly in plants, fungi and bacteria, also hydrolyzes sucrose (and other fructosides) but by a different mechanism: it is a fructosidase, whereas sucrase is a [[Glucosidases|glucosidase]].<ref name=Ullmann>{{cite encyclopedia|author=Hubert Schiweck |author2=Margaret Clarke |author3=Günter Pollach |title=Sugar|encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry|year=2007|publisher=Wiley-VCH|location=Weinheim|doi=10.1002/14356007.a25_345.pub2|isbn=978-3-527-30673-2}}</ref>

==Types==
* {{EC number|3.2.1.10}} is [[sucrase-isomaltase]]
* {{EC number|3.2.1.48}} is [[sucrose alpha-glucosidase]]

==Physiology==
[[Sucrose intolerance]] (also known as congenital sucrase-isomaltase deficiency (CSID), genetic sucrase-isomaltase deficiency (GSID), or sucrase-isomaltase deficiency) occurs when sucrase is not being secreted in the small intestine. With sucrose intolerance, the result of consuming sucrose is excess gas production and often [[diarrhea]] and [[malabsorption]]. [[Lactose intolerance]] is a similar condition that reflects an individual's inability to hydrolyze the disaccharide [[lactose]].

Sucrase is secreted by the tips of the [[Intestinal villus|villi]] of the [[epithelium]] in the [[small intestine]]. Its levels are reduced in response to villi-blunting events such as [[celiac sprue]] and the [[inflammation]] associated with the disorder. The levels increase in [[pregnancy]], [[lactation]], and [[diabetes]] as the villi [[hypertrophy]].

==Use in chemical analysis==
Sucrose is a non-reducing sugar, so will not test positive with [[Benedict's solution]]. To test for sucrose, the sample is treated with sucrase. The sucrose is hydrolysed into [[glucose]] and [[fructose]], with glucose being a [[reducing sugar]], which in turn tests positive with Benedict's solution.{{Citation needed|date=July 2009}}.

==In other species==
[[Cedar waxwing]]s (''Bombycilla cedrorum'') and [[American robin]]s (''Turdus migratorius'') have evolved to lose this enzyme due to their [[insectivorous]] and [[frugivorous]] diets.<ref name="Rio-et-al-1992">{{cite journal | last1=Martínez del Rio | first1=C. | last2=Baker | first2=H. G. | last3=Baker | first3=I. | title=Ecological and evolutionary implications of digestive processes: Bird preferences and the sugar constituents of floral nectar and fruit pulp | journal=[[Experientia]] | publisher=[[Birkhäuser]] | volume=48 | issue=6 | year=1992 | issn=0014-4754 | doi=10.1007/bf01920237 | pages=544–551 | s2cid=25707787}}</ref> This absence produces digestive difficulty if challenged with unusual amounts of the sugar.<ref name="Rio-et-al-1992" />

==References==
<references/>

==External links==
* {{MeshName|Sucrase}}

{{Sugar hydrolases}}
{{Enzymes}}
{{Portal bar|Biology|border=no}}

[[Category:EC 3.2.1]]
[[Category:E-number additives]]


{{3.2-enzyme-stub}}

[[de:Saccharase]]