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intestinal maltase glucoamylase [includes: maltase (alpha-glucosidase); glucoamylase (glucan 1,4-alpha-glucosidase)] (MGAM, MGA, MGAML)
Function:
- may serve as an alternate pathway for starch digestion when luminal alpha-amylase activity is diminished because of immaturity or malnutrition
- may play a unique role in the digestion of malted dietary oligosaccharides used in food manufacturing
- does not undergo intracellular or extracellular proteolytic cleavage
- hydrolysis of terminal, non-reducing (1->4)-linked alpha-D-glucose residues with release of alpha-D-glucose
- hydrolysis of terminal (1->4)-linked alpha-D-glucose residues successively from non-reducing ends of the chains with release of beta-D-glucose
Structure:
- monomer
- N- & O-glycosylated
- sulfated (putative)
- belongs to the glycosyl hydrolase 31 family
- contains 2 P-type (trefoil) domains
Compartment:
- apical cell membrane, brush border
Expression:
- expressed in small intestine, granulocyte, & kidney but not in salivary gland or pancreas
General
amylase
glucosidase
Properties
SIZE: MW = 210 kD
entity length = 1856 aa
COMPARTMENT: cellular membrane
MOTIF: transmembrane domain {13-33}
threonine-rich region {37-83}
MOTIF: threonine residue (SEVERAL)
P-TYPE 1 {88-132}
MOTIF: cysteine residue {C89}
MODIFICATION: cysteine residue {C117}
cysteine residue {C100}
MODIFICATION: cysteine residue {C116}
cysteine residue {C111}
MODIFICATION: cysteine residue {C129}
cysteine residue {C116}
MODIFICATION: cysteine residue {C100}
cysteine residue {C117}
MODIFICATION: cysteine residue {C89}
cysteine residue {C129}
MODIFICATION: cysteine residue {C111}
N-glycosylation site {N134}
MALTASE {197-914}
MOTIF: N-glycosylation site {N294-N478} (4)
aspartate residue {D528}
glutamate residue {E531}
N-glycosylation site {N706-N911} (5)
P-TYPE 2 {952-998}
MOTIF: cysteine residue {C965}
MODIFICATION: cysteine residue {C982}
N-glycosylation site {N976}
cysteine residue {C977}
MODIFICATION: cysteine residue {C995}
cysteine residue {C982}
MODIFICATION: cysteine residue {C965}
N-glycosylation site {N988}
cysteine residue {C995}
MODIFICATION: cysteine residue {C977}
GLUCOAMYLASE {1066-1812}
MOTIF: N-glycosylation site {N1254-N1387} (4)
aspartate residue {D1419}
glutamate residue {E1422}
aspartate residue {D1525}
N-glycosylation site {N1602-N1671} (2)
N-glycosylation site {N1841-N1846} (2)
Database Correlations
OMIM 154360
UniProt O43451
PFAM correlations
Kegg hsa:8972
ENZYME correlations
References
UniProt :accession O43451