Alpha amylase catalytic domain found in an uncharacterized protein family. 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 (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.

Alpha amylase catalytic domain found in Glycosyltrehalose trehalohydrolase (also called Maltooligosyl trehalose Trehalohydrolase). Glycosyltrehalose trehalohydrolase (GTHase) was discovered as part of a coupled system for the production of trehalose from soluble starch. In the first half of the reaction, glycosyltrehalose synthase (GTSase), an intramolecular glycosyl transferase, converts the glycosidic bond between the last two glucose residues of amylose from an alpha-1,4 bond to an alpha-1,1 bond, making a non-reducing glycosyl trehaloside. In the second half of the reaction, GTHase cleaves the alpha-1,4 glycosidic bond adjacent to the trehalose moiety to release trehalose and malto-oligosaccharide. Like isoamylase and other glycosidases that recognize branched oligosaccharides, GTHase contains an N-terminal extension and does not have the conserved calcium ion present in other alpha amylase family enzymes. 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. Glycosyltrehalose Trehalohydrolase Maltooligosyltrehalose Trehalohydrolase

1,4-alpha-glucan branching enzyme [Carbohydrate transport and metabolism].

Pullulanase/glycogen debranching enzyme [Carbohydrate transport and metabolism].

Alpha amylase catalytic domain found in Pullulanase (also called dextrinase; alpha-dextrin endo-1,6-alpha glucosidase), limit dextrinase, and related proteins. Pullulanase is an enzyme with action similar to that of isoamylase; it cleaves 1,6-alpha-glucosidic linkages in pullulan, amylopectin, and glycogen, and in alpha-and beta-amylase limit-dextrins of amylopectin and glycogen. Pullulanases are very similar to limit dextrinases, although they differ in their action on glycogen and the rate of hydrolysis of limit dextrins. 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.

1.4Angstrom Resolution Crystal Structure of Putative alpha Amylase from Salmonella typhimurium. [Salmonella enterica subsp. enterica serovar Typhimurium str. LT2]

CrystalStructure of Chlamydomonas reinhardtii Isoamylase 1 (ISA1) [Chlamydomonas reinhardtii],4J7R_B Crystal Structure of Chlamydomonas reinhardtii Isoamylase 1 (ISA1) [Chlamydomonas reinhardtii],4OKD_A Crystal Structure of Chlamydomonas reinhardtii Isoamylase 1 (ISA1) in complex with maltoheptaose [Chlamydomonas reinhardtii],4OKD_B Crystal Structure of Chlamydomonas reinhardtii Isoamylase 1 (ISA1) in complex with maltoheptaose [Chlamydomonas reinhardtii]

Crystalstructure of glycosyltrehalose trehalohydrolase (E283Q) complexed with maltoheptaose [Saccharolobus solfataricus],3VGH_A Crystal structure of glycosyltrehalose trehalohydrolase (E283Q) complexed with maltotriosyltrehalose [Saccharolobus solfataricus]

CrystalStructure Of Sulfolobus Solfataricus Glycosyltrehalose Trehalohydrolase [Saccharolobus solfataricus],3VGB_A Crystal structure of glycosyltrehalose trehalohydrolase (GTHase) from Sulfolobus solfataricus KM1 [Saccharolobus solfataricus]

CRYSTALSTRUCTURE OF GLYCOSYLTREHALOSE TREHALOHYDROLASE FROM SULFOLOBUS SOLFATARICUS [Saccharolobus solfataricus]

Isoamylase SU1, chloroplastic OS=Zea mays OX=4577 GN=SU1 PE=1 SV=1

Isoamylase 3, chloroplastic OS=Oryza sativa subsp. japonica OX=39947 GN=ISA3 PE=2 SV=1

Isoamylase 3, chloroplastic OS=Arabidopsis thaliana OX=3702 GN=ISA3 PE=1 SV=2

Isoamylase 1, chloroplastic OS=Oryza sativa subsp. japonica OX=39947 GN=ISA1 PE=1 SV=1

Malto-oligosyltrehalose trehalohydrolase OS=Arthrobacter sp. (strain Q36) OX=104027 GN=treZ PE=3 SV=1