Diversity of reaction characteristics of glucan branching enzymes and the fine structure of α-glucan from various sources.
To investigate the functional properties of 10 α-glucan branching enzymes (BEs) from various sources, we determined the chain-length distribution of BE enzymatic products and their phosphorylase-limit dextrins (Φ-LD). All BEs could be classified into either of the three rice BE isozymes: OsBEI, OsBEIIa, or OsBEIIb. Escherichia coli BE (EcoBE) had the same enzymatic properties as OsBEI, while Synechococcus elongatus BE (ScoBE) and Chlorella kessleri BE (ChlBE) had BEIIb-type properties. Human BE (HosBE), yeast BE (SacBE), and two Porphyridium purpureum BEs (PopBE1 and PopBE2) exhibited the OsBEIIa-type properties. Analysis of chain-length profile of Φ-LD of the BE reaction products revealed that EcoBE, ScoBE, PopBE1, and PopBE2 preferred A-chains as acceptors, while OsBEIIb used B-chains more frequently than A-chains. Both EcoBE and ScoBE specifically formed the branch linkages at the third glucose residue from the reducing end of the acceptor chain. The present results provide evidence for the first time that great variation exists as to the preference of BEs for their acceptor chain, either A-chain or B-chain. In addition, EcoBE and ScoBE recognize the location of branching points in their acceptor chain during their branching reaction. Nevertheless, no correlation exists between the primary structure of BE proteins and their enzymatic characteristics.
['Sawada|Takayuki|T|', 'Nakamura|Yasunori|Y|', 'Ohdan|Takashi|T|', 'Saitoh|Asami|A|', 'Francisco|Perigio B|PB|', 'Suzuki|Eiji|E|', 'Fujita|Naoko|N|', 'Shimonaga|Takahiro|T|', 'Fujiwara|Shoko|S|', 'Tsuzuki|Mikio|M|', 'Colleoni|Christophe|C|', 'Ball|Steven|S|']
D015061:1,4-alpha-Glucan Branching Enzyme D000687:Amylopectin D002708:Chlorella D003912:Dextrins D004926:Escherichia coli D005658:Fungi D005936:Glucans D006003:Glycogen D006801:Humans D007527:Isoenzymes D012275:Oryza D006005:Phosphorylases D010802:Phylogeny D044665:Porphyridium D011994:Recombinant Proteins D013045:Species Specificity D013213:Starch D046940:Synechococcus
Glucan branching enzyme Chain-length distribution Amylopectin Glycogen Phosphorylase limit dextrin Starch