Defective SI does not hydrolyze maltotriose

Stable Identifier
R-HSA-5659899
Type
Reaction [transition]
Species
Homo sapiens
Compartment
ReviewStatus
5/5
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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

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

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

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

Hum. Mutat. 2006
Participants
Participates
Catalyst Activity

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

Normal reaction
Functional status

Loss of function of SI mutant dimers [plasma membrane]

Status
Inferred From
Disease
Authored
Reviewed
Created
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