Sucrase-isomaltase

SI
Available structures
PDB	Ortholog search: PDBe RCSB
List of PDB id codes
	3LPO, 3LPP
Identifiers
Aliases	SI, sucrase-isomaltase
External IDs	OMIM: 609845; MGI: 1917233; HomoloGene: 37424; GeneCards: SI; OMA:SI - orthologs
Gene location (Human)
Chr.	Chromosome 3 (human)
End	165,078,496 bp
Gene location (Mouse)
Chr.	Chromosome 3 (mouse)
End	72,875,196 bp
RNA expression pattern
	Top expressed in
	jejunal mucosa; ; mucosa of ileum; ; mucosa of sigmoid colon; ; duodenum; ; sperm; ; rectum; ; testicle; ; epithelium of colon; ; mucosa of transverse colon; ; appendix;
	Top expressed in
	duodenum; ; jejunum; ; ileum; ; colon; ; crypt of lieberkuhn; ; crypt of lieberkuhn of small intestine; ; intestinal epithelium; ; intestinal villus; ; thymus; ; esophagus;
	More reference expression data
	n/a
Gene ontology
Molecular function	sucrose alpha-glucosidase activity; oligo-1,6-glucosidase activity; hydrolase activity, hydrolyzing O-glycosyl compounds; catalytic activity; alpha-1,4-glucosidase activity; hydrolase activity; hydrolase activity, acting on glycosyl bonds; carbohydrate binding;
Cellular component	integral component of membrane; plasma membrane; Golgi apparatus; apical plasma membrane; extracellular exosome; membrane; brush border;
Biological process	polysaccharide digestion; metabolism; carbohydrate metabolic process;
	Sources:Amigo / QuickGO
Orthologs
	6476
	69983
	ENSG00000090402
	ENSMUSG00000027790
	P14410
	F8VQM5
	NM_001041
	NM_001081137
	NP_001032
	NP_001074606
	Wikidata
View/Edit Human	View/Edit Mouse

Sucrase-isomaltase is a bifunctional glucosidase (sugar-digesting enzyme) located on the brush border of the small intestine, encoded by the human gene SI. It is a dual-function enzyme with two GH31 domains, one serving as the isomaltase, the other as a sucrose alpha-glucosidase.^[5]^[6]^[7] It has preferential expression in the apical membranes of enterocytes.^[8] The enzyme’s purpose is to digest dietary carbohydrates such as starch, sucrose and isomaltose. By further processing the broken-down products, energy in the form of ATP can be generated.^[9]

^ ^a ^b ^c GRCh38: Ensembl release 89: ENSG00000090402 – Ensembl, May 2017
^ ^a ^b ^c GRCm38: Ensembl release 89: ENSMUSG00000027790 – Ensembl, May 2017
^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^ Hauri HP, Quaroni A, Isselbacher KJ (October 1979). "Biogenesis of intestinal plasma membrane: posttranslational route and cleavage of sucrase-isomaltase". Proceedings of the National Academy of Sciences of the United States of America. 76 (10): 5183–6. doi:10.1073/pnas.76.10.5183. PMC 413104. PMID 291933.
^ Sjöström H, Norén O, Christiansen L, Wacker H, Semenza G (December 1980). "A fully active, two-active-site, single-chain sucrase.isomaltase from pig small intestine. Implications for the biosynthesis of a mammalian integral stalked membrane protein". The Journal of Biological Chemistry. 255 (23): 11332–8. doi:10.1016/S0021-9258(19)70296-8. PMID 7002920.
^ Rodriguez IR, Taravel FR, Whelan WJ (September 1984). "Characterization and function of pig intestinal sucrase-isomaltase and its separate subunits". European Journal of Biochemistry. 143 (3): 575–82. doi:10.1111/j.1432-1033.1984.tb08408.x. PMID 6479163.
^ Rodríguez D, Ramsay AJ, Quesada V, Garabaya C, Campo E, Freije JM, López-Otín C (June 2013). "Functional analysis of sucrase-isomaltase mutations from chronic lymphocytic leukemia patients". Human Molecular Genetics. 22 (11): 2273–82. doi:10.1093/hmg/ddt078. PMID 23418305.
^ Berg, J. M. et al. Biochemistry, 7th Ed. W.H. Freeman and Company: New York, 2012.

[refGRCh38Ensembl-1] GRCh38: Ensembl release 89: ENSG00000090402 – Ensembl, May 2017

[refGRCm38Ensembl-2] GRCm38: Ensembl release 89: ENSMUSG00000027790 – Ensembl, May 2017

[3] "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.

[4] "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.

[5] Hauri HP, Quaroni A, Isselbacher KJ (October 1979). "Biogenesis of intestinal plasma membrane: posttranslational route and cleavage of sucrase-isomaltase". Proceedings of the National Academy of Sciences of the United States of America. 76 (10): 5183–6. doi:10.1073/pnas.76.10.5183. PMC 413104. PMID 291933.

[Nor&eacute_7002920-6] Sjöström H, Norén O, Christiansen L, Wacker H, Semenza G (December 1980). "A fully active, two-active-site, single-chain sucrase.isomaltase from pig small intestine. Implications for the biosynthesis of a mammalian integral stalked membrane protein". The Journal of Biological Chemistry. 255 (23): 11332–8. doi:10.1016/S0021-9258(19)70296-8. PMID 7002920.

[7] Rodriguez IR, Taravel FR, Whelan WJ (September 1984). "Characterization and function of pig intestinal sucrase-isomaltase and its separate subunits". European Journal of Biochemistry. 143 (3): 575–82. doi:10.1111/j.1432-1033.1984.tb08408.x. PMID 6479163.

[Rodríguez_2013-8] Rodríguez D, Ramsay AJ, Quesada V, Garabaya C, Campo E, Freije JM, López-Otín C (June 2013). "Functional analysis of sucrase-isomaltase mutations from chronic lymphocytic leukemia patients". Human Molecular Genetics. 22 (11): 2273–82. doi:10.1093/hmg/ddt078. PMID 23418305.

[Berg_2012-9] Berg, J. M. et al. Biochemistry, 7th Ed. W.H. Freeman and Company: New York, 2012.

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Sucrase-isomaltase

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