Isolation, purification and characterization of proline dehydrogenase from a Pseudomonas putida POS-F84 isolate

Document Type : Research Paper


Department of Biochemistry, Pasteur Institute of Iran, P.O. Box 1316943551, Tehran, I.R. Iran.


The purpose of this study was to isolate and characterize Proline Dehydrogenase (ProDH) enzyme from
microorganisms isolated from soil in Iran. Isolation and screening of L-proline degradative enzymes from soil
samples was carried out. The isolate was characterized by biochemical markers and 16S rRNA gene
analysis. The target ProDH was purified and the effects of pH and temperature on the activity and stability
were tested. Among the 150 isolates recovered from 30 soil samples, only one was identified as
Pseudomonas putida displayed the highest enzyme activity toward L-proline (2200U/l). The enzyme was
identified as a ProDH and had Km value of 35 mM for L-proline. The molecular mass of the purified ProDH
was about 40 kDa, and determined to be a monomeric protein. The N-terminal amino acid sequences of the
subunit of P. putida enzyme were determined to be MLTSSLTRIIGKSGE. ProDH exhibited high activity at
temperature range of 25 to 35ºC and the highest activity was achieved at 30ºC. It was almost stable at temperatures between 25-30ºC for 2 h. The optimum pH of ProDH activity was determined in pH=8.5 and it was stable in pH range of 8.0-9.0 up to 24 h. The enzyme was purified with a yield of 8.5% and a purification factor of 37.7. Briefly, a ProDH flavonzyme was purified and characterized from a P. putida bacterium. The
specificity of P. putida enzyme toward L-proline is advantageous for the application to the L-proline