Researchers from the University of Illinois (UI) and the University of California are one step closer to recreating nature's most efficient machinery for generating hydrogen gas, according to a news release posted on UI's website on Monday.
Biological enzymes, called hydrogenases, are nature's machinery for making and burning hydrogen gas. These enzymes come in two varieties, iron-iron and nickel-iron named for the elements responsible for driving the chemical reactions. The study focuses on the iron-iron variety because it does the job faster, the researchers said.
The researchers came into the study with a general understanding of the chemical composition of the active sites within the enzyme. They hypothesized that the sites were assembled using 10 parts: four carbon monoxide molecules, two cyanide ions, two iron ions and two groups of a sulfur-containing amino acid called cysteine.
The researchers discovered that it was instead more likely that the enzyme's engine was composed of two identical groups containing five chemicals: two carbon monoxide molecules, one cyanide ion, one iron ion and one cysteine group. The groups form one tightly bonded unit, and the two units combine to give the engine a total of 10 parts.
The laboratory analysis of the lab-synthesized enzyme revealed a final surprise. "Our recipe is incomplete. We now know that 11 bits are required to make the active site engine, not 10, and we are in the hunt for that one final bit," said chemistry professor and study co-author Thomas Rauchfuss.
Though not sure what type of applications this new understanding of the iron-iron hydrogenase enzyme will lead to, the researchers are confident that the new development may help clear the path for the hydrogen fuel industry to move into a larger role in the global push toward more environmentally friendly energy sources.
The findings have been published in the Proceedings of the National Academy of Science.
Editor:Cherie
