Overview for MACiE Entry M0285

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General Information

EC Number: (A member of the Hydrolases, Glycosylases, Glycosidases, i.e. enzymes that hydrolyse O- and S-glycosyl compounds)

Enzyme Name: oligo-1,6-glucosidase

Biological Species: Bacillus cereus (Bacteria)

Catalytic Chain UniprotKB Accession Codes:

  • P21332 - Oligo-1,6-glucosidase

Representative PDB Code: 1uok - CRYSTAL STRUCTURE OF B. CEREUS OLIGO-1,6-GLUCOSIDASE (Resolution = 2.00 Å).

Catalytic CATH Codes:

"Other" CATH Codes:

Display structure information

Overall Reaction:

Image of water

Image of isomaltose

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Image of alpha-D-glucose

Image of D-glucose


Overall Comment: This enzyme can hydrolyse the non-reducing terminal alpha-1,6,glucosidic bonds of isomaltosaccharides, panose and a-limit dextrins, but fails to act on alpha,1,4-glucosidic bonds of maltosaccharides [1]. The anomeric configuration of the substrate is retained, thus the mechanism proceeds via a double displacement process [2,3]. The mechanism here is shown utilising isomaltose.

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Stepwise Description of the Reaction

Step 1Asp displaces the terminal sugar in a nucleophilic substitution reaction, forming a covalent bond between the enzyme and substrate.
Step 2Glu255 deprotonates the water, which initiates a nucleophilic attack on the covalently bound sugar, displacing the Asp199.

View similar reactions (composite manual annotation)

Catalytic Residues Involved

Type Number Chain Location of Function
Asp 199 A Side Chain
Glu 255 A Side Chain
Asp 325 A Side Chain
His 328 A Side Chain


  1. H. Kizaki et al. (1993), J. Biochem., 113, 646-649. Polypeptide folding of Bacillus cereus ATCC7064 oligo-1,6-glucosidase revealed by 3.0 A resolution X-ray analysis.
    Medline: 8370659
  2. K. Watanabe et al. (1997), J. Mol. Biol., 269, 142-153. The refined crystal structure of Bacillus cereus oligo-1,6-glucosidase at 2.0 A resolution: structural characterization of proline-substitution sites for protein thermostabilization.
    Medline: 9193006
  3. J. C. M. Uitdehaag et al. (1996), Nat. Struct. Biol., 6, 432-436. X-ray structures along the reaction pathway of cyclodextrin glycosyltransferase elucidate catalysis in the alpha-amylase family.
    Medline: 10331869
  4. K. Watanabe et al. (2001), Biosci. Biotechnol. Biochem., 65, 2058-2064. Identification of catalytic and substrate-binding site residues in Bacillus cereus ATCC7064 oligo-1,6-glucosidase.
    Medline: 11676021

Homologue information for M0285 (1uok)

CSA Homologues

MACiE Homologues (within the PDB)

MACiE Homologues (within UniprotKB/SwissProt)

Entries with at least one Catalytic CATH code in common (different mechanisms):

MACiE Entry Enzyme Name
EC Number
PDB code CATH code Composite
Reaction Similarity
Catalytic Machinery
M0045 cyclomaltodextrin glucanotransferase

Links to this entry in other databases

Link to EC-PDB-SUM Link to PDB-SUM Link to RCSB PDB Link to PDBe Link to CSA
Link to MetaCyc Link to KEGG Link to BRENDA Link to ExplorENZ
Link to EzCatDB

GOA logo
catalytic activity (molecular function)
oligo-1,6-glucosidase activity (molecular function)
cytoplasm (cellular component)
carbohydrate metabolic process (biological process)
metabolic process (biological process)
hydrolase activity (molecular function)
hydrolase activity, acting on glycosyl bonds (molecular function)
cation binding (molecular function)