It is one of the most important enzymes in medical diagnostics: The so-called - Horseradish Peroxidase- (Horseradish Peroxidase) is used for many medical devices - often it is used when a color change of a test strip is to detect the presence of antibodies or other proteins.
Just recently, however, there is always a shortage of horseradish peroxidase. This is because it is currently extracted from horseradish roots, and this has major disadvantages: The agricultural yield is not always the same, the roots produce not just one version of the enzyme, but a whole family of similar enzymes, and in varying amounts. For this reason, an attempt was made at the Vienna University of Technology to develop a reliable, precise synthesis method in the laboratory. After years of research, they have now succeeded: The production of horseradish peroxidase is now possible with the help of E. coli bacteria. In this process, a very specific enzyme is produced in a precisely reproducible manner, and the process can be scaled up to large-scale industrial production. Two patents for this have already been filed, and the TU Vienna is now looking for industrial partners.
Unpredictable vegetables-When you extract horseradish peroxidase from plants, you don’t get a chemically well-defined substance-, says Oliver Spadiut of the Institute of Process Engineering, Environmental Engineering and Technical Biosciences at TU Wien. -Depending on the environmental conditions, the plant produces different amounts of different enzymes. For certain medical applications, such substances cannot be used at all; for example, such an undefined mixture of different enzymes must not be injected into a human being.
In medical diagnostics, the rules are less strict, and Horseradish peroxidase is used for Western blots or the ELISA method, for example - in these techniques, certain antibodies are coupled to the enzyme. The antibody docks onto a sought molecule, and the enzyme then provides a color change. In this way, the presence of certain molecules can be made visible by color.
-We are currently experiencing shortages in the supply of this enzyme worldwide-, says Oliver Spadiut. -This also has to do with climate change and poor harvests; in other environmental conditions, the plant also changes the composition of the enzymes produced in ways that are difficult to predict.- At the same time, however, global demand is increasing: the market volume for the trade in horseradish peroxidase is estimated to reach over 90 million euros per year in the next few years.
A bacterium to the rescueOliver Spadiut and his team therefore set to work years ago to develop a synthetic production process for the valuable enzyme. The gene for the production of horseradish peroxidase was inserted in the laboratory into yeast cells, mammalian cells and E. coli cells. All three variants actually yielded the desired enzyme, but the best technical solution proved to be the use of E. coli - a very well-known bacterium that has also been used in biotechnology many times before with great success.
However, this does not initially produce a functional enzyme, but rather a so-called -inclusion particle- - a protein that biochemically corresponds to the desired enzyme, but is not folded correctly. In a further step, therefore, the inclusion body must be unraveled and then brought into the correct shape, similar to unwinding a ball of wool and then rolling it up into a well-ordered ball of wool.
Especially in this field of research, the processing of inclusion bodies, Oliver Spadiot’s team has a lot of experience - and so, for the first time worldwide, the TU Vienna succeeded in developing a reliable, reproducible process for the production of horseradish peroxidase. The patents have already been filed, the process is technically mature. -We could start applying the method on an industrial scale tomorrow-, says Oliver Spadiut. -We don’t just have a theoretical concept here, but a proven method that is ready for industrial application.
Next step: cancer therapy?Now that we have succeeded in producing Horseradish peroxidase in a precisely defined, highly pure manner, completely different applications beyond diagnostics are conceivable. -For example, Horseradish peroxidase could now also be used in cancer therapy by coupling it to antibodies that then specifically dock onto cancer cells," says Oliver Spadiut. -We therefore assume that the market volume of Horseradish peroxidase could even increase dramatically through many new applications." Spadiut now wants to hold talks with interested pharmaceutical companies in order to initiate the technological application of the new invention as quickly as possible.
The patenting is carried out with the support of the Research and Transfer Support of the Vienna University of Technology.
You can find more technical information here.