Alpha amylase catalytic domain found in the Glycogen branching enzyme (also called 1,4-alpha-glucan branching enzyme). The glycogen branching enzyme catalyzes the third step of glycogen biosynthesis by the cleavage of an alpha-(1,4)-glucosidic linkage and the formation a new alpha-(1,6)-branch by subsequent transfer of cleaved oligosaccharide. They are part of a group called branching enzymes which catalyze the formation of alpha-1,6 branch points in either glycogen or starch. This group includes proteins from bacteria, eukaryotes, and archaea. 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.

glycogen branching enzyme; Provisional

1,4-alpha-glucan branching protein GlgB.

glycogen branching enzyme; Provisional

1,4-alpha-glucan branching protein GlgB.

Crystalstructure of branching enzyme W610N mutant from Cyanothece sp. ATCC 51142 [Crocosphaera subtropica ATCC 51142],5GQX_A Crystal structure of branching enzyme W610N mutant from Cyanothece sp. ATCC 51142 in complex with maltoheptaose [Crocosphaera subtropica ATCC 51142]

Crystalstructure of branching enzyme D501A mutant from Cyanothece sp. ATCC 51142 [Crocosphaera subtropica ATCC 51142]

Crystalstructure of branching enzyme W610A mutant from Cyanothece sp. ATCC 51142 [Crocosphaera subtropica ATCC 51142]

Crystalstructure of branching enzyme from Cyanothece sp. ATCC 51142 [Crocosphaera subtropica ATCC 51142],5GQV_A Crystal structure of branching enzyme from Cyanothece sp. ATCC 51142 in complex with maltohexaose [Crocosphaera subtropica ATCC 51142],5GQY_A Crystal structure of branching enzyme from Cyanothece sp. ATCC 51142 in complex with maltoheptaose [Crocosphaera subtropica ATCC 51142]

Crystalstructure of branching enzyme L541A mutant from Cyanothece sp. ATCC 51142 [Crocosphaera subtropica ATCC 51142],5GR4_A Crystal structure of branching enzyme L541A mutant from Cyanothece sp. ATCC 51142 in complex with maltoheptaose [Crocosphaera subtropica ATCC 51142]

1,4-alpha-glucan branching enzyme GlgB OS=Thermosynechococcus vestitus (strain IAM M-273 / NIES-2133 / BP-1) OX=197221 GN=glgB PE=3 SV=1

1,4-alpha-glucan branching enzyme GlgB OS=Halothermothrix orenii (strain H 168 / OCM 544 / DSM 9562) OX=373903 GN=glgB PE=3 SV=1

1,4-alpha-glucan branching enzyme GlgB OS=Aromatoleum aromaticum (strain EbN1) OX=76114 GN=glgB PE=3 SV=1

1,4-alpha-glucan branching enzyme GlgB OS=Rubrobacter xylanophilus (strain DSM 9941 / NBRC 16129 / PRD-1) OX=266117 GN=glgB PE=3 SV=1

1,4-alpha-glucan branching enzyme GlgB OS=Nitrosococcus oceani (strain ATCC 19707 / BCRC 17464 / JCM 30415 / NCIMB 11848 / C-107) OX=323261 GN=glgB PE=3 SV=1