Purification and characterization of highly stable aldo-keto reductase from camel (Camelus dromedarius) liver

Aldo-keto reductase (AKR) was purified to homogeneity from camel liver by ion exchange on Q Sepharose, affinity chromatography on Blue-Sepharose and 2,5-ADP-Sepharose 4B. The purification procedure resulted in 32.43-fold purification with 0.65% final yield. Subunit and native molecular weights of the purified enzyme determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration chromatography, were 33kD and 133kD, respectively. The purified AKR exhibited maximal activity at a temperature of 50°C and pH of 7.0. The Km values for NADPH and NADH calculated from the Lineweaver-Burk plot were 0.01 mM and 0.083 mM, respectively, whereas the Km values for m-Nitrobenzaldehyde, 4-Anisaldehyde and P-Benzoquinone were 0.9 mM, 1.11 mM and 0.57 mM, respectively.