Maltase-glucoamylase
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| Location (UCSC) | Chr 7: 141.91 – 142.11 Mb | Chr 6: 40.61 – 40.75 Mb | |||||||
| PubMed search | [3] | [4] | |||||||
| View/Edit Human | View/Edit Mouse |
Maltase-glucoamylase, intestinal is an enzyme that in humans is encoded by the MGAM gene.[5][6]
Maltase-glucoamylase is an alpha-glucosidase digestive enzyme. It consists of two subunits with differing substrate specificity. Recombinant enzyme studies have shown that its N-terminal catalytic domain has highest activity against
Gene
The MGAM gene –– which is located on chromosome 7q34 [8] –– codes for the protein Maltase-Glucoamylase. An alternative name for Maltase-Glucoamylase is glucan 1,4-alpha-glycosidase.[9]
Tissue distribution
Maltase-glucoamylase is a membrane-bound enzyme located in the intestinal walls. This lining of the intestine forms brush border in which food has to pass in order for the intestines to absorb the food.[10]
Enzymatic mechanism
This enzyme is a part of a family of enzymes called
Structure
N-terminal maltase
The N-terminal maltase-glucoamylase enzymatic unit is in turn composed of 5 specific protein domains. The first of the 5 protein domains consist of a
C-terminal glucase
The C-terminal glucase enzymatic unit contains extra binding sites, which allows for it to bind to larger substrates for catalytic digestion.[10] It was originally understood that maltase-glucoamylase's crystalline structure was inherently similar throughout the N and C-termini. Further studies have found that the C-terminus is composed of 21 more amino acid residues than the N-terminus, which account for its difference in function. Sucrase-Isomaltase –– located on chromosome 3q26–– has a similar crystalline structure to maltase-glucoamylase and work in tandem in the human small intestine. They have been derived from a common ancestor, as they both come from the same GH31 family.[8] As a result of having similar properties, both of these enzymes work together in the small intestine in order to convert consumed starch into glucose for metabolic energy. The difference between these two enzymes is that maltase-glucoamylase has a specific activity at the 1-4 linkage of sugar, where at SI has a specific activity at the 1-6 linkage.[10]
See also
- Alpha-glucosidase
- Maltase
References
- ^ a b c ENSG00000282607 GRCh38: Ensembl release 89: ENSG00000257335, ENSG00000282607 – Ensembl, May 2017
- ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000068587 – 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.
- ^ "Entrez Gene: maltase-glucoamylase (alpha-glucosidase)".
- PMID 9446624.
- PMID 18356321.
- ^ PMID 12547908.
- PMID 17485087.
- ^ PMID 18036614.
- ^ "Glycoside hydrolases". CAZypedia. Retrieved 2021-04-30.
- S2CID 42054886.
- S2CID 11245174.
Further reading
- Nichols BL, Avery S, Sen P, Swallow DM, Hahn D, Sterchi E (February 2003). "The maltase-glucoamylase gene: common ancestry to sucrase-isomaltase with complementary starch digestion activities". Proceedings of the National Academy of Sciences of the United States of America. 100 (3): 1432–7. PMID 12547908.
- Takeshita F, Ishii KJ, Kobiyama K, Kojima Y, Coban C, Sasaki S, et al. (August 2005). "TRAF4 acts as a silencer in TLR-mediated signaling through the association with TRAF6 and TRIF". European Journal of Immunology. 35 (8): 2477–85. S2CID 560536.
- Danielsen EM (October 1987). "Tyrosine sulfation, a post-translational modification of microvillar enzymes in the small intestinal enterocyte". The EMBO Journal. 6 (10): 2891–6. PMID 3121301.
- Korpela MP, Paetau A, Löfberg MI, Timonen MH, Lamminen AE, Kiuru-Enari SM (July 2009). "A novel mutation of the GAA gene in a Finnish late-onset Pompe disease patient: clinical phenotype and follow-up with enzyme replacement therapy". Muscle & Nerve. 40 (1): 143–8. S2CID 20120101.
- Sim L, Quezada-Calvillo R, Sterchi EE, Nichols BL, Rose DR (January 2008). "Human intestinal maltase-glucoamylase: crystal structure of the N-terminal catalytic subunit and basis of inhibition and substrate specificity". Journal of Molecular Biology. 375 (3): 782–92. PMID 18036614.
- Naim HY, Sterchi EE, Lentze MJ (December 1988). "Structure, biosynthesis, and glycosylation of human small intestinal maltase-glucoamylase". The Journal of Biological Chemistry. 263 (36): 19709–17. PMID 3143729.
- Ao Z, Quezada-Calvillo R, Sim L, Nichols BL, Rose DR, Sterchi EE, Hamaker BR (May 2007). "Evidence of native starch degradation with human small intestinal maltase-glucoamylase (recombinant)". FEBS Letters. 581 (13): 2381–8. S2CID 23891882.
- Tuğrul S, Kutlu T, Pekin O, Bağlam E, Kiyak H, Oral O (October 2008). "Clinical, endocrine, and metabolic effects of acarbose, a alpha-glucosidase inhibitor, in overweight and nonoverweight patients with polycystic ovarian syndrome". Fertility and Sterility. 90 (4): 1144–8. PMID 18377903.
External links
- PDBe-KB provides an overview of all the structure information available in the PDB for Human Maltase-glucoamylase, intestinal
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