» Articles » PMID: 869927

Oxidation--reduction Potentials of Turkey Liver Xanthine Dehydrogenase and the Origins of Oxidase and Dehydrogenase Behaviour in Molybdenum-containing Hydroxylases

Overview
Journal Biochem J
Specialty Biochemistry
Date 1977 May 1
PMID 869927
Citations 8
Authors
Affiliations
Soon will be listed here.
Abstract

Redox potentials for the various centres in the enzyme xanthine dehydrogenase (EC 1.2.1.37) from turkey liver determined by potentiometric titration in the presence of mediator dyes, with low-temperature electron-paramagnetic-resonance spectroscopy. Values at 25 degrees C in pyrophosphate buffer, pH 8.2, are: Mo(VI)/Mo(V)(Rapid),-350 +/- 20mV; Mo(V) (Rapid)/Mo(IV), -362 +/- 20mV; Fe-S Iox./Fe-S Ired., -295 +/- 15mV; Fe-S IIox./Fe-S IIred., -292 +/- 15mV; FAD/FADH,-359+-20mV; FADH/FADH2, -366 +/- 20mV. This value of the FADH/FADH2 potential, which is 130mV lower than the corresponding one for milk xanthine oxidase [Cammack, Barber & Bray (1976) Biochem. J. 157, 469-478], accounts for many of the differences between the two enzymes. When allowance is made for some interference by desulpho enzyme, then differences in the enzymes' behaviour in titration with xanthine [Barber, Bray, Lowe & Coughlan (1976) Biochem. J. 153, 297-307] are accounted for by the potentials. Increases in the molybdenum potentials of the enzymes caused by the binding of uric acid are discussed. Though the potential of uric acid/xanthine (-440mV) is favourable for full reduction of the dehydrogenase, nevertheless, during turnover, for kinetic reasons, only FADH and very little FADH2 is produced from it. Since only FADH2 is expected to react with O2, lack of oxidase activity by the dehydrogenase is explained. Reactivity of the two enzymes with NAD+ as electron acceptor is discussed in relation to the potentials.

Citing Articles

Role of Uric Acid Metabolism-Related Inflammation in the Pathogenesis of Metabolic Syndrome Components Such as Atherosclerosis and Nonalcoholic Steatohepatitis.

Kushiyama A, Nakatsu Y, Matsunaga Y, Yamamotoya T, Mori K, Ueda K Mediators Inflamm. 2017; 2016:8603164.

PMID: 28070145 PMC: 5192336. DOI: 10.1155/2016/8603164.


Shifting the metallocentric molybdoenzyme paradigm: the importance of pyranopterin coordination.

Rothery R, Weiner J J Biol Inorg Chem. 2014; 20(2):349-72.

PMID: 25267303 DOI: 10.1007/s00775-014-1194-6.


Identification of crucial amino acids in mouse aldehyde oxidase 3 that determine substrate specificity.

Mahro M, Bras N, Cerqueira N, Teutloff C, Coelho C, Romao M PLoS One. 2013; 8(12):e82285.

PMID: 24358164 PMC: 3864932. DOI: 10.1371/journal.pone.0082285.


Oxidation--reduction potentials of molybdenum and iron--sulphur centres in nitrate reductase from Escherichia coli.

Vincent S Biochem J. 1979; 177(2):757-9.

PMID: 373749 PMC: 1186429. DOI: 10.1042/bj1770757.


Comparison of the molybdenum centres of native and desulpho xanthine oxidase. The nature of the cyanide-labile sulphur atom and the nature of the proton-accepting group.

Gutteridge S, Tanner S, Bray R Biochem J. 1978; 175(3):887-97.

PMID: 217354 PMC: 1186150. DOI: 10.1042/bj1750887.


References
1.
Green D . Studies of reversible dehydrogenase systems: The reversibility of the xanthine oxidase system. Biochem J. 1934; 28(4):1550-60. PMC: 1253367. DOI: 10.1042/bj0281550. View

2.
Bray R, Pettersson R, Ehrenberg A . The chemistry of xanthine oxidase. 7. The anaerobic reduction of xanthine oxidase studied by electron-spin resonance and magnetic susceptibility. Biochem J. 1961; 81:178-89. PMC: 1243315. DOI: 10.1042/bj0810178. View

3.
KRENITSKY T, Tuttle J, Cattau Jr E, Wang P . A comparison of the distribution and electron acceptor specificities of xanthine oxidase and aldehyde oxidase. Comp Biochem Physiol B. 1974; 49(4):687-703. DOI: 10.1016/0305-0491(74)90256-9. View

4.
Smith S, Rajagopalan K, Handler P . Purification and properties of xanthine dehydroganase from Micrococcus lactilyticus. J Biol Chem. 1967; 242(18):4108-17. View

5.
MASSEY V, Muller F, Feldberg R, Schuman M, Sullivan P, Howell L . The reactivity of flavoproteins with sulfite. Possible relevance to the problem of oxygen reactivity. J Biol Chem. 1969; 244(15):3999-4006. View