glycosyl hydrolase family 36 (GH36). GH36 enzymes occur in prokaryotes, eukaryotes, and archaea with a wide range of hydrolytic activities, including alpha-galactosidase, alpha-N-acetylgalactosaminidase, stachyose synthase, and raffinose synthase. All GH36 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. GH36 members 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.

Melibiase. Glycoside hydrolase families GH27, GH31 and GH36 form the glycoside hydrolase clan GH-D. Glycoside hydrolase family 36 can be split into 11 families, GH36A to GH36K. This family includes enzymes from GH36A-B and GH36D-K and from GH27.

Alpha-galactosidase [Carbohydrate transport and metabolism].

Alpha amylase catalytic domain found in archaeal and bacterial Alpha-amylases (also called 1,4-alpha-D-glucan-4-glucanohydrolase). AmyA (EC 3.2.1.1) catalyzes the hydrolysis of alpha-(1,4) glycosidic linkages of glycogen, starch, related polysaccharides, and some oligosaccharides. This group includes firmicutes, bacteroidetes, and proteobacteria. The Alpha-amylase family comprises the largest family of glycoside hydrolases (GH), with the majority of enzymes acting on starch, glycogen, and related oligo- and polysaccharides. These proteins catalyze the transformation of alpha-1,4 and alpha-1,6 glucosidic linkages with retention of the anomeric center. The protein is described as having 3 domains: A, B, C. A is a (beta/alpha) 8-barrel; B is a loop between the beta 3 strand and alpha 3 helix of A; C is the C-terminal extension characterized by a Greek key. The majority of the enzymes have an active site cleft found between domains A and B where a triad of catalytic residues (Asp, Glu and Asp) performs catalysis. Other members of this family have lost the catalytic activity as in the case of the human 4F2hc, or only have 2 residues that serve as the catalytic nucleophile and the acid/base, such as Thermus A4 beta-galactosidase with 2 Glu residues (GH42) and human alpha-galactosidase with 2 Asp residues (GH31). The family members are quite extensive and include: alpha amylase, maltosyltransferase, cyclodextrin glycotransferase, maltogenic amylase, neopullulanase, isoamylase, 1,4-alpha-D-glucan maltotetrahydrolase, 4-alpha-glucotransferase, oligo-1,6-glucosidase, amylosucrase, sucrose phosphorylase, and amylomaltase.

CtsY (cyclic tetrasaccharide-synthesizing enzyme Y)-like. CtsY is a bacterial 3-alpha-isomaltosyltransferase, first identified in Arthrobacter globiformis, that produces cyclic tetrasaccharides together with a closely related enzyme CtsZ. CtsY and CtsZ both have a glycosyl hydrolase family 31 (GH31) catalytic domain; CtsZ belongs to a different subfamily. 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.

Structureof alpha-galactosidase from Lactobacillus acidophilus NCFM, PtCl4 derivative [Lactobacillus acidophilus NCFM],2XN0_B Structure of alpha-galactosidase from Lactobacillus acidophilus NCFM, PtCl4 derivative [Lactobacillus acidophilus NCFM],2XN1_A Structure of alpha-galactosidase from Lactobacillus acidophilus NCFM with TRIS [Lactobacillus acidophilus NCFM],2XN1_B Structure of alpha-galactosidase from Lactobacillus acidophilus NCFM with TRIS [Lactobacillus acidophilus NCFM],2XN1_C Structure of alpha-galactosidase from Lactobacillus acidophilus NCFM with TRIS [Lactobacillus acidophilus NCFM],2XN1_D Structure of alpha-galactosidase from Lactobacillus acidophilus NCFM with TRIS [Lactobacillus acidophilus NCFM]

Structureof alpha-galactosidase from Lactobacillus acidophilus NCFM with galactose [Lactobacillus acidophilus NCFM]

Crystalstructure of GH36 alpha-galactosidase AgaA from Geobacillus stearothermophilus [Geobacillus stearothermophilus],4FNR_B Crystal structure of GH36 alpha-galactosidase AgaA from Geobacillus stearothermophilus [Geobacillus stearothermophilus],4FNR_C Crystal structure of GH36 alpha-galactosidase AgaA from Geobacillus stearothermophilus [Geobacillus stearothermophilus],4FNR_D Crystal structure of GH36 alpha-galactosidase AgaA from Geobacillus stearothermophilus [Geobacillus stearothermophilus]

Crystalstructure of GH36 alpha-galactosidase AgaA A355E D548N from Geobacillus stearothermophilus in complex with raffinose [Geobacillus stearothermophilus],4FNT_B Crystal structure of GH36 alpha-galactosidase AgaA A355E D548N from Geobacillus stearothermophilus in complex with raffinose [Geobacillus stearothermophilus],4FNT_C Crystal structure of GH36 alpha-galactosidase AgaA A355E D548N from Geobacillus stearothermophilus in complex with raffinose [Geobacillus stearothermophilus],4FNT_D Crystal structure of GH36 alpha-galactosidase AgaA A355E D548N from Geobacillus stearothermophilus in complex with raffinose [Geobacillus stearothermophilus]

Crystalstructure of GH36 alpha-galactosidase AgaA A355E from Geobacillus stearothermophilus [Geobacillus stearothermophilus],4FNP_B Crystal structure of GH36 alpha-galactosidase AgaA A355E from Geobacillus stearothermophilus [Geobacillus stearothermophilus],4FNP_C Crystal structure of GH36 alpha-galactosidase AgaA A355E from Geobacillus stearothermophilus [Geobacillus stearothermophilus],4FNP_D Crystal structure of GH36 alpha-galactosidase AgaA A355E from Geobacillus stearothermophilus [Geobacillus stearothermophilus],4FNS_A Crystal structure of GH36 alpha-galactosidase AgaA A355E from Geobacillus stearothermophilus in complex with 1-deoxygalactonojirimycin [Geobacillus stearothermophilus],4FNS_B Crystal structure of GH36 alpha-galactosidase AgaA A355E from Geobacillus stearothermophilus in complex with 1-deoxygalactonojirimycin [Geobacillus stearothermophilus],4FNS_C Crystal structure of GH36 alpha-galactosidase AgaA A355E from Geobacillus stearothermophilus in complex with 1-deoxygalactonojirimycin [Geobacillus stearothermophilus],4FNS_D Crystal structure of GH36 alpha-galactosidase AgaA A355E from Geobacillus stearothermophilus in complex with 1-deoxygalactonojirimycin [Geobacillus stearothermophilus]

Alpha-galactosidase Mel36A OS=Lactobacillus acidophilus (strain ATCC 700396 / NCK56 / N2 / NCFM) OX=272621 GN=melA PE=1 SV=1

Alpha-galactosidase AgaA OS=Geobacillus stearothermophilus OX=1422 GN=agaA PE=1 SV=1

Alpha-galactosidase 1 OS=Pediococcus pentosaceus OX=1255 GN=agaR PE=3 SV=1

Alpha-galactosidase OS=Escherichia coli OX=562 GN=rafA PE=1 SV=1

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