Concept explainers
To review:
The structures ofproducts of the reaction between nitrogenase complex and substrates hydrogen cyanide, dinitroge, nnd acetylene.
Introduction:
Nitrogenase complex is present in all the species that can fix nitrogen. It is produced by bacteria such as cyanobacteria. This reduces nitrogen (N2) to ammonia (NH3). This is the only enzyme that can catalyze the reaction for nitrogen fixation.
Explanation of Solution
The nitrogenase complex consists of two proteins called dinitrogenase as well asdinitrogenase reductase. The dinitrogenase is heterotetramer of MoFe protein. The dinitrogenase reductase is called Fe(ferrous) protein. It contains Mg-ATP (magnesium-adenosine triphosphate)-binding sites. In the reaction catalyzed by this complex, there is a transfer of electrons from (4Fe-4S) cluster in Fe protein. The Fe transfers the electrons to Mo-Fe protein. The transfer of electrons leads to a reduction of H+. The incoming N2 exchanges withH+ within the active site to form stable intermediates. So, the reaction of nitrogenasecomplex with the given substrates is as follows:
When nitrogenase complex reacts with cyanide, it gives two product, sethylamine and methan, elong with ammonia:
When nitrogenase complex reacts with acetylene, it gives ethylene as a product:
When nitrogenase complex reacts with dinitrogen, it gives hydrazine or ammonia as a product:
Thus, it can be concluded that the products of substrates hydrogen cyanide, acetylen, endnitrogen are methylamine, ethylene, and hydrazine, respectively.
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Chapter 14 Solutions
Biochemistry: The Molecular Basis of Life
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