Characterization of a recombinant L-ribose isomerase from Mycetocola miduiensis and its application for the production of L-ribulose

Publication date: Available online 13 January 2020Source: Enzyme and Microbial TechnologyAuthor(s): Shahid Mahmood, Muhammad Waheed Iqbal, Tahreem Riaz, Hinawi A.M. Hassanin, Yingying Zhu, Dawei Ni, Wanmeng MuAbstractAn enzyme, L-ribose isomerase (L-RI), mostly catalyzes the isomerization of L-ribose and L-ribulose. These so-called rare sugars are essential for the treatment of cancer and other viral diseases. In the present study, L-ribose isomerase produced from a bacterium, Mycetocola miduiensis (Mm-LRIse), by using L-ribose as a carbon source. The recombinant L-ribose isomerase gene was cloned and overexpressed from M. miduiensis and purified with an exclusive band of 32 kDa by nickel-affinity chromatography. This gene possessed 267 amino acids protein having an estimated molecular weight of 29,568.17 Da. The native molecular weight of Mm-LRIse estimated by HPLC was 134.84 kDa. The recombinant L-ribose isomerase was highly active in sodium phosphate (50 mM) buffer at 40 °C and pH 7.5, showing the specific activity up to 47.40 U mg-1. Mm-LRIse showed no significant enhancement in activity with metallic ions except Mn2+ and Co2+. The values of Km, Kcat, Kcat/Km and Vmax of Mm-LRIse against L-ribose substrate were 42.48 mM, 9259.26 min−1, 217.43 min−1 mM−1, and 277.78 U mg-1 respectively. At equilibrium, the L-ribulose transformation rate was nearly 32% (6.34 g L−1) using 20 g L−1 of L-ribose. The results revealed that the Mm-LRIse enzyme has a...
Source: Enzyme and Microbial Technology - Category: Biotechnology Source Type: research