ISSN:
1574-6968
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Abstract The hydrogenase of the extremely thermophilic archaebacterium Thermococcus stetteri has been isolated. The procedure involved four steps, the last stage being preparative electrophoresis, with an overall yield of 40%. The molecular mass was estimated to be approx. 106 kDa. Analysis for metal content found iron and nickel in the ratio 13:1. Flavin was also detected in the enzyme and identified as FMN. The hydrogenase activity was relatively insensitive to inhibition by carbon monoxide, Ki 67 μM. This behaviour is indicative of a nickel-iron type hydrogenase. Electron paramagnetic resonance spectroscopy of the enzyme showed signals characteristic of iron-sulfur clusters. The spectra of the hydrogen-reduced T. stetteri hydrogenase, recorded at 70 K, indicated the presence of a single type of [2Fe-2S]cluster. Below 10 K, the spectra were complex, and indicated the presence of other iron-sulfur clusters with extremely fast electron-spin relaxation rates, interpreted as [4Fe-4S] clusters, and minor amounts of [3Fe-4S]clusters. These properties indicate that T. stetteri hydrogenase is related to the hydrogenases of Pyrococcus furiosus, a hyperthermophilic archaebacterium, and Alcaligenes eutrophus.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1574-6968.1996.tb08410.x
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