Characterization of a novel (R)-mandelate dehydrogenase from Pseudomonas putida NUST506

(R)-Mandelate dehydrogenase (RMDH) has the potential to produce chiral mandelic acid. The present work reports isolation and identification of a Pseudomonas putida NUST506 contained RMDH. The strain was rod shaped with polar flagella, approximately 0.6-0.9 mu m wide and 1.7-2.3 mu m long. The RMDH was purified from the strain. The molecular weight of the enzyme was calculated to be 61 kDa. The optimal conditions for RMDH were pH 8.5 and 30 degrees C. At the optimum condition, the K-m and k(cat) of the RMDH were 2.0 x 10(-2) mM and 0.9 s(-1) for (R)-mandelic acid, 1.8 x 10(-2) mM and 0.9 s(-1) for NAD(+), as well as 1.5 x 10(-2) mM and 0.3 s(-1) for NADP(+), respectively. The enzyme activity was increased by K+ and dithiothreitol (DTT), but obviously inhibited by Zn2+, Hg2+, sodium dodecyl sulfate (SDS) and ethylenediamine tetra-acetic acid (EDTA). (C) 2015 Published by Elsevier B.V.