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Nitrogen fixation is a chemical process by which molecular dinitrogen (N 2) is converted into ammonia (NH 3). [1] It occurs both biologically and abiologically in chemical industries. Biological nitrogen fixation or diazotrophy is catalyzed by enzymes called nitrogenases. [2]
Abiological nitrogen fixation describes chemical processes that fix (react with) N 2, usually with the goal of generating ammonia. The dominant technology for abiological nitrogen fixation is the Haber process, which uses iron-based heterogeneous catalysts and H 2 to convert N 2 to NH 3. This article focuses on homogeneous (soluble) catalysts ...
The terminal nitrogen is susceptible to electrophilic attack, allowing for the fixation of nitrogen to ammonia in the presence of acid. In this way, Mo(N 2) 2 (dppe) 2 serves as a model for biological nitrogen fixation. Carbon-nitrogen bonds can also be formed with this complex through condensation reactions with ketones and aldehydes, and ...
Interest in such complexes arises because N 2 comprises the majority of the atmosphere and because many useful compounds contain nitrogen. Biological nitrogen fixation probably occurs via the binding of N 2 to those metal centers in the enzyme nitrogenase, followed by a series of steps that involve electron transfer and protonation. [12]
Heterocysts or heterocytes are specialized nitrogen-fixing cells formed during nitrogen starvation by some filamentous cyanobacteria, such as Nostoc, Cylindrospermum, and Anabaena. [1] They fix nitrogen from dinitrogen (N 2) in the air using the enzyme nitrogenase, in order to provide the cells in the filament with nitrogen for biosynthesis. [2]
Nitrogen is present in the environment in a wide variety of chemical forms including organic nitrogen, ammonium (NH + 4), nitrite (NO − 2), nitrate (NO − 3), nitrous oxide (N 2 O), nitric oxide (NO) or inorganic nitrogen gas (N 2). Organic nitrogen may be in the form of a living organism, humus or in the intermediate products of organic ...
The nif genes are genes encoding enzymes involved in the fixation of atmospheric nitrogen into a form of nitrogen available to living organisms. The primary enzyme encoded by the nif genes is the nitrogenase complex which is in charge of converting atmospheric nitrogen (N 2) to other nitrogen forms such as ammonia which the organism can use for various purposes.
However Entamoeba histolytica was found to possess a simplified and non-redundant NIF (nitrogen fixation)-like system for the Fe-S cluster formation, composed of only a catalytic component, NifS, and a scaffold component, NifU. EhNifS and EhNifU were found to be necessary and sufficient for Fe-S clusters of non-nitrogenase Fe-S proteins to form ...