Hydrogen gas from enzyme production

December 6, 2017

Researchers at Freie Universität Berlin and the Ruhr-Universität Bochum have uncovered a crucial reaction principle of hydrogen-producing enzymes. Teams led by Dr. Ulf-Peter Apfel in Bochum and Dr. Sven T. Stripp at Freie Universität investigated the production of molecular hydrogen in single-cell green algae. They were able to demonstrate how the enzyme succeeds in transferring two electrons in succession to two hydrogen ions and thereby assume stable intermediate states. Hydrogen gas is viewed as the energy source of the future. Thus, there is considerable industrial interest in elucidating the mechanism of biological production. The findings were published in the latest issue of the journal Angewandte Chemie.

In living nature a variety of chemical reactions take place very slowly. The use of enzymes increases the likelihood or the speed of a reaction (catalysis). Frequently the supply and removal of electrons also plays a role - this is referred to as reduction and oxidation. Special enzymes, the hydrogenases, accelerate the conversion of (protons) to with high efficiency. They absorb excess electrons that are generated during photosynthesis and release hydrogen gas as a by-product. This process can be described as a reduction of two protons with two electrons, whereby the reaction takes place in several steps.

"After receiving a first electron, an is typically less likely to accept a second one," stresses Dr. Sven Stripp. In spite of this, two electrons can be transferred to two protons. Using synthetic hydrogenase enzymes, advanced infrared spectroscopy, and electrochemical methods, the researchers investigated how this is possible. They demonstrated that the uptake of an electron at the catalytic center of the enzyme is coupled with the binding of a proton. The positive charge of the proton compensates for the negative charge of the electron. In chemistry this process is known as proton-coupled electron transfer (PCET). "Thus, the second electron can be transferred with comparable probability as the first one," says Dr. Ulf-Peter Apfel.

According to the authors, this observation has high relevance for understanding the catalytic mechanism of hydrogenases and for the design of synthetic complexes for the production of gas. In addition, the scientists speculate that PCET processes could explain the uptake of multiple in other enzymes as well because many of these macromolecules carry catalytic centers of iron and sulfur atoms, similar to those of hydrogenases.

Explore further: How enzymes produce hydrogen

More information: Moritz Senger et al. Protonengekoppelte Reduktion des katalytischen [4Fe-4S]-Zentrums in [FeFe]-Hydrogenasen, Angewandte Chemie (2017). DOI: 10.1002/ange.201709910

Related Stories

How enzymes produce hydrogen

July 21, 2017

Researchers at Ruhr-Universität Bochum and the Freie Universität Berlin have clarified the crucial catalytic step in the production of hydrogen by enzymes. The enzymes, called [FeFe]-hydrogenases, efficiently turn electrons ...

Evolution of a bacterial enzyme in green algae

July 12, 2017

A new jigsaw piece in the evolution of green algae has been identified by researchers at Ruhr-Universität Bochum together with colleagues from Max Planck Institute in Mülheim an der Ruhr. They analysed the hydrogen-producing ...

New X-ray spectroscopy explores hydrogen-generating catalyst

November 22, 2017

Using a newly developed technique, researchers from Japan, Germany and the U.S. have identified a key step in production of hydrogen gas by a bacterial enzyme. Understanding these reactions could be important in developing ...

How green algae assemble their enzymes

March 27, 2017

Researchers at Ruhr-Universität Bochum have analysed how green algae manufacture complex components of a hydrogen-producing enzyme. The enzyme, known as the hydrogenase, may be relevant for the biotechnological production ...

Recommended for you

Bioluminescent worm found to have iron superpowers

December 14, 2017

Researchers at Scripps Institution of Oceanography at the University of California San Diego have made a discovery with potential human health impacts in a parchment tubeworm, the marine invertebrate Chaetopterus sp., that ...

Scientists develop new, rapid pipeline for antimicrobials

December 14, 2017

With hospitals more often reaching for antibiotics of last resort to fight infections and recent Ebola and Zika outbreaks crossing borders like never before, the worldwide scientific community has been challenged with developing ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.