ISSN:
1432-072X
Keywords:
Frankia
;
Nitrogenase
;
Oxygen protection
;
Alnus rubra isolate
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract O2 protection of nitrogenase in a cultured Frankia isolate from Alnus rubra (HFPArI3) was studied in vivo. Evidence for a passive gas diffusion barrier in the vesicles was obtained by kinetic analysis of in vivo O2 uptake and acetylene reduction rates in response to substrate concentration. O2 of NH 4 + -grown cells showed an apparent K m O2 of approximately 1μM O2. In N2-fixing cultures a second K m O2 of about 215 μM O2 was observed. Thus, respiration remained unsaturated by O2 at air-saturation levels. In vivo, the apparent K m for acetylene was more than 10-fold greater than reported in vitro values. These data were inter oreted as evidence for a gas diffusion barrier in the vesicles but not vegetative filaments of Frankia sp. HFPArI3.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00401993
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