N-terminal domain of glycosyl hydrolase family 31 (GH31). This family is found N-terminal to the glycosyl-hydrolase domain of Glycoside hydrolase family 31 (GH31). GH31 includes the glycoside hydrolases alpha-glucosidase (EC 3.2.1.20), alpha-1,3-glucosidase (EC 3.2.1.84), alpha-xylosidase (EC 3.2.1.177), sucrase-isomaltase (EC 3.2.1.48 and EC 3.2.1.10), as well as alpha-glucan lyase (EC 4.2.2.13). 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 of the catalytic domain have been identified as the catalytic nucleophile and the acid/base, respectively. A loop of the N-terminal beta-sandwich domain is part of the active site pocket.

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

Clostridium CPE1046-like. CPE1046 is an uncharacterized Clostridium perfringens protein with a glycosyl hydrolase family 31 (GH31) domain. The domain architecture of CPE1046 and its orthologs includes a C-terminal fibronectin type 3 (FN3) domain and a coagulation factor 5/8 type C domain in addition to the GH31 domain. 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.

putative alpha-glucosidase; Provisional

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, GH31 alpha-N-acetylgalactosaminidase [Enterococcus faecalis ATCC 10100]

GH31alpha-N-acetylgalactosaminidase from Enterococcus faecalis [Enterococcus faecalis ATCC 10100],6M77_A GH31 alpha-N-acetylgalactosaminidase from Enterococcus faecalis in complex with N-acetylgalactosamine [Enterococcus faecalis ATCC 10100]

ChainA, GH31 alpha-N-acetylgalactosaminidase [Enterococcus faecalis ATCC 10100]

CrystalStructure of Alpha-Xylosidase from Escherichia coli [Escherichia coli],1WE5_B Crystal Structure of Alpha-Xylosidase from Escherichia coli [Escherichia coli],1WE5_C Crystal Structure of Alpha-Xylosidase from Escherichia coli [Escherichia coli],1WE5_D Crystal Structure of Alpha-Xylosidase from Escherichia coli [Escherichia coli],1WE5_E Crystal Structure of Alpha-Xylosidase from Escherichia coli [Escherichia coli],1WE5_F Crystal Structure of Alpha-Xylosidase from Escherichia coli [Escherichia coli]

Structureof the YicI thiosugar Michaelis complex [Escherichia coli],2F2H_B Structure of the YicI thiosugar Michaelis complex [Escherichia coli],2F2H_C Structure of the YicI thiosugar Michaelis complex [Escherichia coli],2F2H_D Structure of the YicI thiosugar Michaelis complex [Escherichia coli],2F2H_E Structure of the YicI thiosugar Michaelis complex [Escherichia coli],2F2H_F Structure of the YicI thiosugar Michaelis complex [Escherichia coli]

Alpha-xylosidase OS=Escherichia coli (strain K12) OX=83333 GN=yicI PE=1 SV=2

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

Alpha-xylosidase XylQ OS=Lactiplantibacillus pentosus OX=1589 GN=xylQ PE=1 SV=1