Chapter XIII The Acetylene Reduction Test for Nitrogen Fixation
1972; Academic Press; Linguagem: Inglês
10.1016/s0580-9517(08)70604-4
ISSN0580-9517
Autores Tópico(s)Ammonia Synthesis and Nitrogen Reduction
ResumoThis chapter discusses the acetylene reduction test for nitrogen fixation. The acetylene reduction test provides strong evidence for nitrogenase and is of considerable value both at the ecological level and in enzymology. With a good gas–liquid chromatograph, its sensitivity is about 1000 times that of traditional Kjeldahl analyses. This fact must be borne in mind when activities assessed by other methods are being compared with acetylene reduction. It is possible to obtain extracts or organisms with apparently high acetylene reducing activity but undetectable N2 fixation or 15N2 incorporation. Usually, a simple calculation of specific rates shows that these are experimental artefacts, but ATP-activated reduction of acetylene to ethylene might occur by mechanisms unrelated to nitrogen fixation. Critical experiments should, therefore, be checked by tests involving actual reaction with nitrogen and, where possible, tests involving repression of the system by ammonium ions.
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