Purification and basic biochemical characterization of 19 recombinant
plant peroxidase isoenzymes produced in Pichia pastoris
The plant enzyme horseradish peroxidase (HRP) is used in several important industrial and medical
applications, of which especially biosensors and diagnostic kits describe an emerging field. Although
there is an increasing demand for high amounts of pure enzyme preparations, HRP is still isolated from
the plant as a mixture of different isoenzymes with different biochemical properties. Based on a recent
next generation sequencing approach of the horseradish transcriptome, we produced 19 individual
HRP isoenzymes recombinantly in the yeast Pichia pastoris. After optimizing a previously reported 2-step
purification strategy for the recombinant isoenzyme HRP C1A by substituting an unfavorable size exclusion
chromatography step with an anion exchange step using a monolithic column, we purified the 19
HRP isoenzymes with varying success. Subsequent basic biochemical characterization revealed differences
in catalytic activity, substrate specificity and thermal stability of the purified HRP preparations.
The preparations of the isoenzymes HRP A2A and HRP A2B were found to be highly interesting candidates
for future applications in diagnostic kits with increased sensitivity