glycosyl hydrolase family 31 (GH31); uncharacterized subgroup. This family represents an uncharacterized GH31 enzyme subgroup found in bacteria and eukaryotes. Enzymes of the GH31 family possess a wide range of different hydrolytic activities including alpha-glucosidase (glucoamylase and sucrase-isomaltase), alpha-xylosidase, 6-alpha-glucosyltransferase, 3-alpha-isomaltosyltransferase and alpha-1,4-glucan lyase. All GH31 enzymes cleave a terminal carbohydrate moiety from a substrate that varies considerably in size, depending on the enzyme, and may be either a starch or a glycoprotein.

Alpha-glucosidase, glycosyl hydrolase family GH31 [Carbohydrate transport and metabolism].

Glycosyl hydrolases family 31. Glycosyl hydrolases are key enzymes of carbohydrate metabolism. Family 31 comprises of enzymes that are, or similar to, alpha- galactosidases.

glycosyl hydrolase family 31 (GH31). GH31 enzymes occur in prokaryotes, eukaryotes, and archaea with a wide range of hydrolytic activities, including alpha-glucosidase (glucoamylase and sucrase-isomaltase), alpha-xylosidase, 6-alpha-glucosyltransferase, 3-alpha-isomaltosyltransferase and alpha-1,4-glucan lyase. All GH31 enzymes cleave a terminal carbohydrate moiety from a substrate that varies considerably in size, depending on the enzyme, and may be either a starch or a glycoprotein. In most cases, the pyranose moiety recognized in subsite -1 of the substrate binding site is an alpha-D-glucose, though some GH31 family members show a preference for alpha-D-xylose. Several GH31 enzymes can accommodate both glucose and xylose and different levels of discrimination between the two have been observed. Most characterized GH31 enzymes are alpha-glucosidases. In mammals, GH31 members with alpha-glucosidase activity are implicated in at least three distinct biological processes. The lysosomal acid alpha-glucosidase (GAA) is essential for glycogen degradation and a deficiency or malfunction of this enzyme causes glycogen storage disease II, also known as Pompe disease. In the endoplasmic reticulum, alpha-glucosidase II catalyzes the second step in the N-linked oligosaccharide processing pathway that constitutes part of the quality control system for glycoprotein folding and maturation. The intestinal enzymes sucrase-isomaltase (SI) and maltase-glucoamylase (MGAM) play key roles in the final stage of carbohydrate digestion, making alpha-glucosidase inhibitors useful in the treatment of type 2 diabetes. GH31 alpha-glycosidases are retaining enzymes that cleave their substrates via an acid/base-catalyzed, double-displacement mechanism involving a covalent glycosyl-enzyme intermediate. Two aspartic acid residues have been identified as the catalytic nucleophile and the acid/base, respectively.

alpha-xylosidase YicI-like. YicI alpha-xylosidase is a glycosyl hydrolase family 31 (GH31) enzyme that catalyzes the release of an alpha-xylosyl residue from the non-reducing end of alpha-xyloside substrates such as alpha-xylosyl fluoride and isoprimeverose. YicI forms a homohexamer (a trimer of dimers). All GH31 enzymes cleave a terminal carbohydrate moiety from a substrate that varies considerably in size, depending on the enzyme, and may be either a starch or a glycoprotein. The YicI family corresponds to subgroup 4 in the Ernst et al classification of GH31 enzymes.

ChainA, Alpha-xylosidase [Lactococcus lactis subsp. cremoris MG1363],7WJD_A Chain A, Alpha-xylosidase [Lactococcus lactis subsp. cremoris MG1363],7WJE_A Chain A, Alpha-xylosidase [Lactococcus lactis subsp. cremoris MG1363],7WJF_A Chain A, Alpha-xylosidase [Lactococcus lactis subsp. cremoris MG1363]

ChainA, Alpha-xylosidase [Lactococcus lactis subsp. cremoris MG1363],7WJ9_B Chain B, Alpha-xylosidase [Lactococcus lactis subsp. cremoris MG1363],7WJ9_C Chain C, Alpha-xylosidase [Lactococcus lactis subsp. cremoris MG1363],7WJ9_D Chain D, Alpha-xylosidase [Lactococcus lactis subsp. cremoris MG1363],7WJ9_E Chain E, Alpha-xylosidase [Lactococcus lactis subsp. cremoris MG1363],7WJ9_F Chain F, Alpha-xylosidase [Lactococcus lactis subsp. cremoris MG1363],7WJA_A Chain A, Alpha-xylosidase [Lactococcus lactis subsp. cremoris MG1363],7WJB_A Chain A, Alpha-xylosidase [Lactococcus lactis subsp. cremoris MG1363],7WLG_A Chain A, Alpha-xylosidase [Lactococcus lactis subsp. cremoris MG1363],7WLG_B Chain B, Alpha-xylosidase [Lactococcus lactis subsp. cremoris MG1363],7WLG_C Chain C, Alpha-xylosidase [Lactococcus lactis subsp. cremoris MG1363],7WLG_D Chain D, Alpha-xylosidase [Lactococcus lactis subsp. cremoris MG1363],7WLG_E Chain E, Alpha-xylosidase [Lactococcus lactis subsp. cremoris MG1363],7WLG_F Chain F, Alpha-xylosidase [Lactococcus lactis subsp. cremoris MG1363]

Flavobacteriumjohnsoniae GH31 dextranase, FjDex31A [Flavobacterium johnsoniae UW101],6JR6_B Flavobacterium johnsoniae GH31 dextranase, FjDex31A [Flavobacterium johnsoniae UW101],6JR6_C Flavobacterium johnsoniae GH31 dextranase, FjDex31A [Flavobacterium johnsoniae UW101],6JR6_D Flavobacterium johnsoniae GH31 dextranase, FjDex31A [Flavobacterium johnsoniae UW101],6JR7_A Flavobacterium johnsoniae GH31 dextranase, FjDex31A, complexed with glucose [Flavobacterium johnsoniae UW101],6JR7_B Flavobacterium johnsoniae GH31 dextranase, FjDex31A, complexed with glucose [Flavobacterium johnsoniae UW101],6JR7_C Flavobacterium johnsoniae GH31 dextranase, FjDex31A, complexed with glucose [Flavobacterium johnsoniae UW101],6JR7_D Flavobacterium johnsoniae GH31 dextranase, FjDex31A, complexed with glucose [Flavobacterium johnsoniae UW101]

Cycloalternan-formingenzyme from Listeria monocytogenes in complex with pentasaccharide substrate [Listeria monocytogenes EGD-e]

Flavobacteriumjohnsoniae GH31 dextranase, FjDex31A, mutant D412A complexed with isomaltotriose [Flavobacterium johnsoniae UW101],6JR8_B Flavobacterium johnsoniae GH31 dextranase, FjDex31A, mutant D412A complexed with isomaltotriose [Flavobacterium johnsoniae UW101],6JR8_C Flavobacterium johnsoniae GH31 dextranase, FjDex31A, mutant D412A complexed with isomaltotriose [Flavobacterium johnsoniae UW101],6JR8_D Flavobacterium johnsoniae GH31 dextranase, FjDex31A, mutant D412A complexed with isomaltotriose [Flavobacterium johnsoniae UW101]

Alpha-xylosidase OS=Saccharolobus solfataricus (strain ATCC 35092 / DSM 1617 / JCM 11322 / P2) OX=273057 GN=xylS PE=1 SV=1

Alpha-glucosidase 2 OS=Bacillus thermoamyloliquefaciens OX=1425 PE=3 SV=1

Alpha-xylosidase BoGH31A OS=Bacteroides ovatus (strain ATCC 8483 / DSM 1896 / JCM 5824 / BCRC 10623 / CCUG 4943 / NCTC 11153) OX=411476 GN=BACOVA_02646 PE=1 SV=1

Neutral alpha-glucosidase AB OS=Homo sapiens OX=9606 GN=GANAB PE=1 SV=3

Oligosaccharide 4-alpha-D-glucosyltransferase OS=Cellvibrio japonicus (strain Ueda107) OX=498211 GN=agd31B PE=1 SV=1