Developing and engineering enzymes for manufacturing amylose
2007
Yanase, M.(Ezaki Glico Co. Ltd., Osaka (Japan)) | Takaha, T. | Kuriki, T.
Amylose is a functional biomaterial and is expected to be used for various industries. However at present, manufacturing of amylose is not done, since the purification of amylose from starch is very difficult. It has been known that amylose can be produced in vitro by using alpha-glucan phosphorylases. In order to obtain alpha-glucan phosphorylase suitable for manufacturing amylose, we isolated an alpha-glucan phosphorylase gene from Thermus aquaticus and expressed it in Escherichia coli. We also obtained thermostable alpha-glucan phosphorylase by introducing amino acid replacement onto potato enzyme. alpha-Glucan phosphorylase is suitable for the synthesis of amylose; the only problem is that it requires an expensive substrate, glucose 1-phosphate. We have avoided this problem by using alpha-glucan phosphorylase either with sucrose phosphorylase or cellobiose phosphorylase, where inexpensive raw material, sucrose or cellobiose, can be used instead. In these combined enzymatic systems, alpha-glucan phosphorylase is a key enzyme. This paper summarizes our work on engineering practical alpha-glucan phosphorylase for industrial processes and its use in the enzymatic synthesis of essentially linear amylose and other glucose polymers.
اظهر المزيد [+] اقل [-]