Biochemical and biophysical studies on cytochrome aa3. VI. Reaction of cyanide with oxidized and reduced enzyme

Buuren, K.J.H. van; Nicholls, Peter; Gelder, B.F. Van

doi:10.1016/0005-2728(72)90057-6

Cited by 163 publications

(89 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Whereas conventional binding of cyanide to heme u"; is slow (k, =i 2 M-' -s-l for the 'fast' enzyme [1,5,21]) and gives rise to a substantial red shift of the Soret band associated ' The initial observations described in this work were subsequently confirmed and extended in collaborative research between P.N. and A.A.K.…”

Section: Discussionmentioning

confidence: 52%

A new spectral intermediate in cyanide binding with the oxidized cytochrome c oxidase

et al. 1993

View full text Add to dashboard Cite

Reaction of cyanide with oxidized cytochrome c oxidase at a low concentration of the ligand and pH >8 reveals an initial phase, not reported earlier, associated with a small blue shift of the absorption spectrum, which is followed by a conventional red shift of the heme us;. The initial blue shift resembles the spectral changes induced under the same conditions by low concentrations of azide and it is not observed in the presence of 0.3 mM azide. It is suggested that, similarly to NO, cyanide and HN, cannot only bind to heme a3 but to Cu',' as well, perturbing the spectrum of& indirectly. A rapid binding to Cu',+ could provide the long-sought intermediate m the cyanide reaction with heme a';, the existence of which is implied by the Michaelis-Menten type kinetics of the latter process.

show abstract

Section: Discussionmentioning

confidence: 52%

A new spectral intermediate in cyanide binding with the oxidized cytochrome c oxidase

et al. 1993

View full text Add to dashboard Cite

show abstract

“…3A). The latter value corresponds to the heme a of other cytochrome c oxidases (36,37), whereas the extinction coefficient of the heme a 587 is unusually high. In low temperature difference spectra (77 K) the absorbance peak at 587 nm is downshifted to 582 nm (with a shoulder at 573 nm).…”

Section: Resultsmentioning

confidence: 92%

The Archaeal SoxABCD Complex Is a Proton Pump in Sulfolobus acidocaldarius

Gleißner

Kaiser

Antonopoulos

et al. 1997

Journal of Biological Chemistry

View full text Add to dashboard Cite

The thermoacidophilic archaeon Sulfolobus acidocaldarius expresses a very unusual quinol oxidase, which contains four heme a redox centers and one copper atom. The enzyme was solubilized with dodecyl maltoside and purified to homogeneity by a combination of hydrophobic interaction and anion exchange chromatography. The oxidase complex consists of four polypeptide subunits with apparent molecular masses of 64, 39, 27, and 14 kDa that are encoded by the soxABCD operon (Lü bben, M., Kolmerer, B., and Saraste, M. (1992) EMBO J. 11, 805-812). The optical spectra and redox potentials of the SoxABCD complex have been characterized, and the absorption coefficients of the contributing cytochromes a 587 and aa 3 were determined. The EPR spectra indicate the presence of three low spin and one high spin heme species, the latter associated with the binuclear heme Cu B site. Standard midpoint potentials of the cytochrome a 587 heme centers were determined as ؉210 and ؉270 mV, respectively. The maximum turnover of the complex (1300 s ؊1 at 65°C) was found to be about three times greater than that of the previously studied isolated cytochrome aa 3 subunit alone (Gleissner, ؉ /e ؊ ratio >1 was determined, identifying the SoxABCD complex as a proton-pumping quinol oxidase. According to structural analysis, the cytochrome aa 3 moiety of the complex does not contain the signature of a H ؉ pumping channel as identified in Rhodobacter sphaeroides or Paracoccus denitrificans. Therefore, for H ؉ translocation, a mechanism different from that in typical heme-copper oxidases of the aa 3 or bo 3 type is discussed.M

show abstract

“…Spectrophotometric evidence from mitochondrial and purified enzyme preparations has indicated that HCN binds with both the reduced and oxidized forms of cytochrome a3 (21)(22)(23)(24); however, the rate of interaction with oxidized cytochrome a3 is two orders of magnitude slower than the reaction rate for reduced cytochrome a3 and cyanide, leading others to conclude that the kinetically significant site of cyanide inter-ruption of mitochondrial electron transport is at the reduced cytochrome a3 level (24).…”

Section: Introductionmentioning

confidence: 99%

Cyanide-induced cytochrome a,a3 oxidation-reduction responses in rat brain in vivo.

Piantadosi¹,

Sylvia²,

Jöbsis³

1983

J. Clin. Invest.

View full text Add to dashboard Cite

Biochemical and biophysical studies on cytochrome aa3. VI. Reaction of cyanide with oxidized and reduced enzyme

Cited by 163 publications

References 20 publications

A new spectral intermediate in cyanide binding with the oxidized cytochrome c oxidase

A new spectral intermediate in cyanide binding with the oxidized cytochrome c oxidase

The Archaeal SoxABCD Complex Is a Proton Pump in Sulfolobus acidocaldarius

Cyanide-induced cytochrome a,a3 oxidation-reduction responses in rat brain in vivo.

Contact Info

Product

Resources

About