Diversity of reaction characteristics of glucan branching enzymes and the fine structure of alpha-glucan from various sources

作者：Sawada Takayuki; Nakamura Yasunori^*; Ohdan Takashi; Saitoh Asami; Francisco Perigio B Jr; Suzuki Eiji; Fujita Naoko; Shimonaga Takahiro; Fujiwara Shoko; Tsuzuki Mikio; Colleoni Christophe; Ball Steven

来源：Archives of Biochemistry and Biophysics, 2014, 562: 9-21.

DOI：10.1016/j.abb.2014.07.032

• Glucan branching enzyme
• Chain-length distribution
• Phosphorylase limit dextrin
• Amylopectin
• Glycogen
• Starch

To investigate the functional properties of 10 alpha-glucan branching enzymes (BEs) from various sources, we determined the chain-length distribution of BE enzymatic products and their phosphorylase-limit dextrins (Phi-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 Phi-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.

• 出版日期2014-11-15