pullulanase, type I. Pullulan is an unusual, industrially important polysaccharide in which short alpha-1,4 chains (maltotriose) are connected in alpha-1,6 linkages. Enzymes that cleave alpha-1,6 linkages in pullulan and release maltotriose are called pullulanases although pullulan itself may not be the natural substrate. This family consists of pullulanases related to the subfamilies described in TIGR02102 and TIGR02103 but having a different domain architecture with shorter sequences. Members are called type I pullulanases.

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.

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

pullulanase, extracellular, Gram-positive. Pullulan is an unusual, industrially important polysaccharide in which short alpha-1,4 chains (maltotriose) are connected in alpha-1,6 linkages. Enzymes that cleave alpha-1,6 linkages in pullulan and release maltotriose are called pullulanases although pullulan itself may not be the natural substrate. In contrast, a glycogen debranching enzyme such GlgX, homologous to this family, can release glucose at alpha,1-6 linkages from glycogen first subjected to limit degradation by phosphorylase. Characterized members of this family include a surface-located pullulanase from Streptococcus pneumoniae () and an extracellular bifunctional amylase/pullulanase with C-terminal pullulanase activity (.

alpha-amylase/limit dextrinase

ChainA, Pullulanase [Ruminococcus bromii]

ChainA, Pullulanase [Ruminococcus bromii]

ChainA, Pullulanase [Ruminococcus bromii]

ChainA, Pullulanase [Ruminococcus bromii]

Pullulanasefrom Bacillus acidopullulyticus [Bacillus acidopullulyticus]

Pullulanase OS=Thermotoga maritima (strain ATCC 43589 / DSM 3109 / JCM 10099 / NBRC 100826 / MSB8) OX=243274 GN=pulA PE=1 SV=2

Pullulanase OS=Bacillus subtilis (strain 168) OX=224308 GN=amyX PE=1 SV=1

Pullulanase A OS=Streptococcus pneumoniae serotype 4 (strain ATCC BAA-334 / TIGR4) OX=170187 GN=spuA PE=1 SV=1

Pullulanase A OS=Streptococcus pneumoniae serotype 2 (strain D39 / NCTC 7466) OX=373153 GN=spuA PE=3 SV=1

Pullulanase A OS=Streptococcus pneumoniae OX=1313 GN=spuA PE=1 SV=1