Sucrase-Isomaltase (SI) Enzyme

AKA: Oligo-1,6-Glucosidase, Alpha-Methylglucosidase, Isomaltase, Oligosaccharide Alpha-1,6-Glucosidase, Sucrase-Alpha-Dextrinase, Limit Dextrine, So Maltase, Exo-Oligo-1,6-Glucosidase, Dextrin 6Alpha-Glucanohydrolase, Alpha-Limit Dextrine, Dextrin 6-Glucanohydrolase.
Context:
- It can (typically) be expressed in (mammalian?) Intestinal Brush Borders.
- It can cleave Disaccharides Sucrose and Maltose to their component Monosaccharides.
- Its is a Hydrolase that Catalyzes the Cleavage of the Disaccharides Sucrose and Maltose to their component Monosaccharides; it occurs complexed with α-Dextrinase in the brush border of the Intestinal Mucosa and deficiency of the complex causes the Disaccharide intolerance Sucrase-Isomaltase deficiency.
- It can be indetified as : EC 3.2.1.10 [1], NCBI 6476 [2], HGNC 10856 [3], OMIM 609845 [4], PDB 3LPO [5], RefSeq NM 001041, UniProt P14410 [6].
Example(s):
- Sucrose Alpha-Glucosidase.
- Staphylococcus Aureus PLC http://www.uniprot.org/uniprot/P09978
- Bacillus Cereus PLC http://www.uniprot.org/uniprot/P09598
- PMID 2120057: “The gene coding for Bacillus cereus ATCC7064 (mesophile ) oligo-1,6-glucosidase was cloned within a 2.8-kb SalI-EcoRI fragment of DNA, using the plasmid pUC19 as a vector and Escherichia coli C600 as a host .E. coli C600 bearing the hybrid plasmid pBCE4 accumulated oligo-1,6-glucosidase in the cytoplasm .”
Counter-Example(s):
See: Mesophile, Enzyme, Gene.

References

(Wikipedia, 2019) ⇒ https://en.wikipedia.org/wiki/Sucrase-isomaltase Retrieved:2019-3-28.
- Sucrase-isomaltase (EC 3.2.1.10), is a glucosidase enzyme located on the brush border of the small intestine ^[1]^[2]^[3]. It has preferential expression in the apical membranes of enterocytes.^[4] 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.^[5]

(EC,2019) ⇒ https://enzyme.expasy.org/EC/3.2.1.10 Retrieved:2019-3-28.
- QUOTE: This enzyme, like EC 3.2.1.33, can release an alpha-1->6-linked glucose, whereas the shortest chain that can be released by EC 3.2.1.41, EC 3.2.1.142 and EC 3.2.1.68 is maltose.
  It also hydrolyzes isomaltulose (palatinose), isomaltotriose and panose, but has no action on glycogen or phosphorylase limit dextrin.
  The enzyme from intestinal mucosa is a single polypeptide chain that also catalyzes the reaction of EC 3.2.1.48.
  Differs from EC 3.2.1.33 in its preference for short-chain substrates and in its not requiring the 6-glucosylated residue to be at a branch point, i.e. linked at both C-1 and C-4.

(OMIM,2019) ⇒ http://www.omim.org/entry/609845. Retrieved:2019-3-28.
- QUOTE: The SI gene encodes sucrase-isomerase, an enzyme composed of 2 highly similar sucrase and isomaltase subunits, originating from a single polypeptide precursor, pro-SI. It is a type II transmembrane glycoprotein with preferential expression in the apical membranes of the polarized enterocytes of the intestinal brush border membrane, where it is essential for the processing of dietary carbohydrates. The mature intestinal protein is a heterodimer, generated through proteolytic cleavage in the intestinal lumen, in which both sucrase and isomaltase domains remain associated by noncovalent interactions (summary by Rodriguez et al., 2013^[4]).

↑ 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. 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 / FEBS. 143 (3): 575–82. doi:10.1111/j.1432-1033.1984.tb08408.x. PMID 6479163.
↑ ^4.0 ^4.1 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.