Substrate specificity of a mannose-6-phosphate isomerase from Bacillus subtilis and its application in the production of L-ribose.
The uncharacterized gene previously proposed as a mannose-6-phosphate isomerase from Bacillus subtilis was cloned and expressed in Escherichia coli. The maximal activity of the recombinant enzyme was observed at pH 7.5 and 40 degrees C in the presence of 0.5 mM Co(2+). The isomerization activity was specific for aldose substrates possessing hydroxyl groups oriented in the same direction at the C-2 and C-3 positions, such as the d and l forms of ribose, lyxose, talose, mannose, and allose. The enzyme exhibited the highest activity for l-ribulose among all pentoses and hexoses. Thus, L-ribose, as a potential starting material for many L-nucleoside-based pharmaceutical compounds, was produced at 213 g/liter from 300-g/liter L-ribulose by mannose-6-phosphate isomerase at 40 degrees C for 3 h, with a conversion yield of 71% and a volumetric productivity of 71 g liter(-1) h(-1).
Yeom
Soo-Jin
SJ
Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang-Dong, Gwangjin-Gu, Seoul 143-701, South Korea.
Ji
Jung-Hwan
JH
Kim
Nam-Hee
NH
Park
Chang-Su
CS
Oh
Deok-Kun
DK
D001412:Bacillus subtilis / Q000201:enzymology*; D001426:Bacterial Proteins / Q000378:metabolism*; D003001:Cloning, Molecular; D003035:Cobalt / Q000494:pharmacology; D020536:Enzyme Activators / Q000494:pharmacology; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D006601:Hexoses / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008359:Mannose-6-Phosphate Isomerase / Q000378:metabolism*; D010429:Pentoses / Q000378:metabolism; D012266:Ribose / Q000378:metabolism*; D013379:Substrate Specificity; D013696:Temperature
D001426:Bacterial Proteins; D020536:Enzyme Activators; D006601:Hexoses; D010429:Pentoses; D003035:Cobalt; D012266:Ribose; D008359:Mannose-6-Phosphate Isomerase