earticle

영어

The rpiB gene, encoding ribose-5-phosphate isomerase (RpiB) from Clostridium thermocellum, was cloned and expressed in Escherichia coli. Substrate specificity of the expressed enzyme was investigated with hexose and pentose. The RpiB enzyme had narrow specificity for L-talose, D-ribose, L-ribose, D-allose, L-allose or D-talose which converted to the respective ketose. Interestingly, structures of those substrates showed the same OH direction of carbon C2, C3 and C4. Also the enzyme had a inverse reaction such as D-ribulose, D-psicose, L-tagatose or L-ribulose. Among substrate, L-talose as aldose show the highest Km and Kcat/Km values of 35.3 mM and 467.2 μM-1/s-1, respectively.