Department of Chemical Enzymology, Faculty of Chemistry, Lomonosov
Moscow State University, Moscow, 119192, Russia. E-mail: vit@enz.chem.msu.ru
A comparative study of the thermostability of NAD+-dependent
formate dehydrogenases (FDHs; EC 1.2.1.2) from methylotrophic bacteria
Pseudomonas sp.101 and Moraxella sp. C1, the
methanol-utilizing yeast Candida boidinii , and plants
Arabidopsis thaliana and Glycine max (soybean) was performed.
All the enzymes studied were produced by expression in E.coli
cells. The enzymes were irreversibly inactivated in one stage according
to first-order reaction kinetics. The FDH from Pseudomonas sp.101 appeared as the most thermostable enzyme; its counterpart from
Glycine max exhibited the lowest stability. The enzymes from
Moraxella sp. C1, C.boidinii , and Arabidopsis thaliana
showed similar thermostability profiles. The temperature dependence of
the inactivation rate constant of A.thaliana FDH was studied. The
data of differential scanning calorimetry was complied with the
experimental results on the inactivation kinetics of these enzymes.
Values of the melting heat were determined for all the enzymes studied.
