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.

neutral alpha-glucosidase C, neutral alpha-glucosidase AB. This subgroup includes the closely related glycosyl hydrolase family 31 (GH31) isozymes, neutral alpha-glucosidase C (GANC) and the alpha subunit of heterodimeric neutral alpha-glucosidase AB (GANAB). Initially distinguished on the basis of differences in electrophoretic mobility in starch gel, GANC and GANAB have been shown to have other differences, including those of substrate specificity. GANC and GANAB are key enzymes in glycogen metabolism that hydrolyze terminal, non-reducing 1,4-linked alpha-D-glucose residues from glycogen in the endoplasmic reticulum. The GANC/GANAB family includes the alpha-glucosidase II (ModA) from Dictyostelium discoideum as well as the alpha-glucosidase II (GLS2, or ROT2 - Reversal of TOR2 lethality protein 2) from Saccharomyces cerevisiae.

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.

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]

Bacteroidesovatus Xyloglucan PUL GH31 [Bacteroides ovatus],5JOV_A Bacteroides ovatus Xyloglucan PUL GH31 with bound 5FIdoF [Bacteroides ovatus]

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

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]

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

Probable glucan 1,3-alpha-glucosidase OS=Arabidopsis thaliana OX=3702 GN=PSL5 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