Defective SI does not hydrolyze maltotriose

Stable Identifier
R-HSA-5659899
Type
Reaction [transition]
Species
Homo sapiens
Compartment
extracellular region, plasma membrane
ReviewStatus
5/5
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Defective SI does not hydrolyze maltotriose
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Mutations that disrupt the catalytic activity or strongly interfere with proper folding, glycosylation and transport of SI (sucrase-isomaltase) are inferred to block the cleavage of maltotriose to maltose and glucose, based on the experimentally demonstrated failure of these SI mutant proteins to hydrolyze maltose (e.g., Sander et al. 2005) and the broad substrate specificity of the normal enzyme (Sim et al. 2010).
Literature References
PubMed ID Title Journal Year
20356844 Structural basis for substrate selectivity in human maltase-glucoamylase and sucrase-isomaltase N-terminal domains

Sim, L, Willemsma, C, Mohan, S, Naim, HY, Pinto, BM, Rose, DR

J. Biol. Chem. 2010
16329100 Novel mutations in the human sucrase-isomaltase gene (SI) that cause congenital carbohydrate malabsorption

Sander, P, Alfalah, M, Keiser, M, Korponay-Szabo, I, Kovács, JB, Leeb, T, Naim, HY

Hum. Mutat. 2006
Participants
Input
Participates
as an event of
Catalyst Activity

alpha-1,4-glucosidase activity of SI mutant dimers [plasma membrane]

Physical Entity
SI mutant dimers [plasma membrane] (Homo sapiens)
Activity
alpha-1,4-glucosidase activity (GO:0004558)
Normal reaction
maltotriose + H2O => maltose + D-glucose (sucrase-isomaltase) (Homo sapiens)
Functional status

Loss of function of SI mutant dimers [plasma membrane]

Normal Entity
Disease Entity
Status
Inferred From
Defective SI does not hydrolyze Mal (Homo sapiens)
Disease
Cross References
Mondo
Authored
D'Eustachio, P  (2015-02-15)
Reviewed
Naim, HY  (2015-02-15)
Amiri, M  (2015-02-15)
Jassal, B  (2015-01-29)
Created
D'Eustachio, P  (2014-12-24)
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