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.

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-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.

xylosidase XylS-like. XylS is a glycosyl hydrolase family 31 (GH31) alpha-xylosidase found in prokaryotes, eukaryotes, and archaea, that catalyzes the release of alpha-xylose from the non-reducing terminal side of the alpha-xyloside substrate. XylS has been characterized in Sulfolobus solfataricus where it hydrolyzes isoprimeverose, the p-nitrophenyl-beta derivative of isoprimeverose, and xyloglucan oligosaccharides, and has transxylosidic activity. 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 XylS family corresponds to subgroup 3 in the Ernst et al classification of GH31 enzymes.

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]

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]

CrystalStructure of Apo Agd31B, alpha-transglucosylase in Glycoside Hydrolase Family 31 [Cellvibrio japonicus],4B9Z_A Crystal Structure of Agd31B, alpha-transglucosylase, complexed with Acarbose [Cellvibrio japonicus],4BA0_A Crystal Structure of Agd31B, alpha-transglucosylase, complexed with 5F-alpha-GlcF [Cellvibrio japonicus]

CrystalStructure of Agd31B, alpha-transglucosylase in Glycoside Hydrolase Family 31, in complex with Cyclophellitol Aziridine probe CF022 [Cellvibrio japonicus Ueda107],5I24_A Crystal Structure of Agd31B, alpha-transglucosylase in Glycoside Hydrolase Family 31, in complex with Cyclophellitol Aziridine probe CF021 [Cellvibrio japonicus Ueda107],5NPB_A Crystal Structure of cjAgd31B (alpha-transglucosylase from Glycoside Hydrolase Family 31) in complex with alpha Cyclophellitol Cyclosulfate probe ME647 [Cellvibrio japonicus],5NPE_A Crystal Structure of cjAgd31B (alpha-transglucosylase from Glycoside Hydrolase Family 31) in complex with beta Cyclophellitol Aziridine probe KY358 [Cellvibrio japonicus Ueda107]

ChainA, Alpha-xylosidase [Xanthomonas citri pv. citri str. 306],7KNC_A Chain A, Alpha-xylosidase [Xanthomonas citri pv. citri str. 306]

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

Alpha-xylosidase OS=Emericella nidulans (strain FGSC A4 / ATCC 38163 / CBS 112.46 / NRRL 194 / M139) OX=227321 GN=agdD PE=1 SV=1

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

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