Open AccessInhibition of Desulfovibrio gigas hydrogenase with copper salts and other metal ions
Author(s) -
FERNANDEZ Victor M.,
RUA Maria L.,
REYES Presentación,
CAMMACK Richard,
HATCHIKIAN E. Claude
Publication year - 1989
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1989.tb15135.x
Subject(s) - hydrogenase , chemistry , desulfovibrio , enzyme , copper , inorganic chemistry , proteases , medicinal chemistry , photochemistry , biochemistry , organic chemistry , sulfate
The effect of several transition metals on the activity of Desulfovibrio gigas hydrogenase has been studied. Co(II) and Ni(II) at a concentration of 1 mM did not modify the activity of the enzyme; nor did they affect the pattern of activation/deactivation. Cu(II) inhibited the active hydrogenase, prepared by treatment with hydrogen, but had little effect on the ‘unready’ enzyme unless a reductant such as ascorbate was present, in which case inactivation took place either in air or under argon. Hg(II) also inactivated the enzyme irreversible in the ‘unready’ state without the requirement for reductants. The reaction of H 2 uptake with methyl viologen was much more sensitive to inhibition than the H 2 /tritium exchange activity. EPR spectra of this preparation showed that the rates of decline were [3Fe‐4S] signal > H 2 ‐uptake activity > Ni‐A signal. Similar results were obtained when the protein was treated with Hg(II). The results demonstrate that the [3Fe‐4S] cluster is not essential for H 2 ‐uptake activity with methyl viologen, but the integrity of [4Fe‐4S] clusters is probably necessary to catalyze the reduction of methyl viologen with hydrogen. D. gigas hydrogenase was found to be highly resistant to digestion by proteases.