Abstract:
:Recent studies of the reaction mechanism of the molybdenum-containing enzyme xanthine oxidase are presented. The pH-dependence of both the steady-state and rapid reaction kinetics of the enzyme exhibits is bell-shaped, with pK(a)s for the acid and alkaline limbs of 6.6 and 7.4, respectively. These are assigned to ionizations of an active site base and substrate, respectively, with the implication that enzyme acts on the neutral rather than monoanionic form of the purine substrate. A computational study provides evidence that in the course of the reaction tautomerization of substrate occurs, with a proton moving from N-3 to N-9 in the course of the reaction - enzyme facilitation of this tautomerization may contribute as much as 24 kcal/mol in transition state stabilization for the reaction. Electron spin echo (ESEEM) and electron-nuclear double resonance (ENDOR) studies of the so-called "very rapid" Mo(V) intermediate of the reaction, the latter work using a newly synthesized form of the substrate 2-hydroxy-6-methylpurine that has been selectively isotopically labeled at C-8, indicates that product is bound to the molybdenum of the active site in a simple, end-on fashion, consistent with a reaction mechanism involving nucleophilic attack of a (deprotonated) Mo-OH on the C-8 position of substrate. A kinetic study using a series of purines has failed to identify a correlation between the one-electron reduction potential for substrate and catalytic effectiveness, indicating that a reaction mechanism initiated by one-electron, outer-sphere electron transfer is unlikely. Finally, a consideration of the active site structure in the context of the above work suggests specific amino acid residues to target for site-directed mutagenesis studies. Preliminary experiments with two such mutants are entirely consistent with the proposed catalytic roles of two active site glutamate residues.
journal_name
J Inorg Biochemjournal_title
Journal of inorganic biochemistryauthors
Choi EY,Stockert AL,Leimkühler S,Hille Rdoi
10.1016/j.jinorgbio.2003.11.010subject
Has Abstractpub_date
2004-05-01 00:00:00pages
841-8issue
5eissn
0162-0134issn
1873-3344pii
S0162013403004483journal_volume
98pub_type
杂志文章abstract::Sulfur- and selenium-containing amino acids are of great biological importance, but their metal-binding properties with biologically-relevant metal ions are not well investigated. Stability constants of the methionine, selenomethionine, methylcysteine, and methylselenocysteine with Cu(II) and Fe(II) were determined by...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/j.jinorgbio.2019.03.001
更新日期:2019-06-01 00:00:00
abstract::Dentin remineralization is of clinical relevance in the therapy of caries and dentin hypersensitivity. This study is aimed at gaining more insights on a molecular scale, through IR spectroscopy, into dentin demineralization and remineralization. The dentin demineralization by ethylenediaminetetraacetic acid, EDTA (17%...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/j.jinorgbio.2019.01.004
更新日期:2019-04-01 00:00:00
abstract::A heterodinuclear (Ru(II), Co(III)) metal polypyridyl complex [(phen)(2)Ru(bpibH(2))Co(phen)(2)](5+) {phen = 1,10-phenanthroline, bpibH(2) = 1,4-bis([1,10]phebanthroline-[5,6-d]imidazol-2-yl)-benzene} has been designed and synthesized. The comparative study on the interactions of the Ru(II)-Co(III) complex with calf t...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/j.jinorgbio.2010.08.006
更新日期:2010-12-01 00:00:00
abstract::Rats were fed 100 microM aluminum maltolate for one year in their drinking water. Brain aluminum contents have increased 4.2-fold in the aluminum-treated group, whereas no significant changes in the body weight, brain weight, and brain protein content were observed. Long-term aluminum feeding induced apoptosis as asse...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/j.jinorgbio.2005.06.032
更新日期:2005-10-01 00:00:00
abstract::[Pt(L)(2)(ox)] (1), [Pt(2-OMeL)(2)(ox)] (2), [Pt(3-OMeL)(2)(ox)] (3), [Pt(2,3-diOMeL)(2)(ox)] (4), [Pt(2,4-diOMeL)(2)(ox)] (5), [Pt(3,4-diOMeL)(2)(ox)] (6) and [Pt(3,5-diOMeL)(2)(ox)].4H(2)O (7) platinum(II) oxalato (ox) complexes were synthesized using the reaction of potassium bis(oxalato)platinate(II) dihydrate wit...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/j.jinorgbio.2010.02.005
更新日期:2010-06-01 00:00:00
abstract::Aiming to investigate the use of tridentate ligands to develop new bireductively activated prodrugs, two N(2)O-donor ligands (HL1: [(2-hydroxybenzyl)(2-(imidazol-2-yl)ethyl)]amine; and HL2: [(2-hydroxybenzyl)(2-(pyridil-2-yl)ethyl]amine) were used to synthesize new Co(III) complexes, 1 and 2. Both complexes were chara...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/j.jinorgbio.2009.07.008
更新日期:2009-10-01 00:00:00
abstract::Preparation of metal/protein hybrids is growing into important topics in the field of bioinorganic chemistry. X-ray crystal structure analyses of them provide direct information on unique interactions of metal cations or metal cofactors to understand and design enzymatic functions. In this mini review, the authors foc...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章,评审
doi:10.1016/j.jinorgbio.2007.06.025
更新日期:2007-11-01 00:00:00
abstract::The binding of acetazolamide, p-fluorobenzensulfonamide, p-toluenesulfonamide, and sulfanilamide to nickel(II)-substituted carbonic anhydrase II has been studied by 1H NMR and electronic absorption spectroscopies. These inhibitors bind to the metal ion forming 1:1 complexes and their affinity constants were determined...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/0162-0134(92)84012-c
更新日期:1992-03-01 00:00:00
abstract::In this study we report the synthesis, characterization and a thorough biological evaluation of twelve organoruthenium-8-hydroxyquinolinato (Ru-hq) complexes. The chosen hqH ligands bear various halogen atoms in different positions which enables to study effect of the substituents on physico-chemical and biological pr...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/j.jinorgbio.2018.05.009
更新日期:2018-09-01 00:00:00
abstract::We have expressed and purified metal-resistance and metal regulatory proteins from the bacterial determinants of resistance to heavy metals and utilised these in the development of biosensors for heavy metals. Both the metallothionein from the cyanobacterium Synechococcus PCC 7942 and the MerR regulatory protein from ...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/s0162-0134(99)00234-2
更新日期:2000-04-01 00:00:00
abstract::A whole-cell biohybrid catalyst where a (pentamethylcyclopentadienyl)rhodium(III) (Cp*Rh(III)) complex was covalently incorporated into the cavity of nitrobindin (NB), a β-barrel protein, was prepared on an E. coli cell surface to produce isoquinolines via C(sp2)-H bond activation. In this whole-cell biohybrid system,...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/j.jinorgbio.2020.111352
更新日期:2021-01-08 00:00:00
abstract::Dysregulation of apoptosis and necrosis is central to many diseases and non-invasive imaging of cell death is an important clinical objective to stage disease or to monitor treatment progress. The C2A domain of rat synaptotagmin I binds to phosphatidylserine (PS) exposed during cell death and modification to its lysin...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/j.jinorgbio.2013.07.017
更新日期:2013-11-01 00:00:00
abstract::The nitrophorins (NP) of the adult blood-sucking insect Rhodnius prolixus fall into two pairs based on sequence identity (NP1,4 (90%) and NP2,3 (79%)), which differ significantly in the size of side chains of residues which contact the heme. These residues include those in the distal pocket of NP2 (I120) and NP1 (T121...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/j.jinorgbio.2011.06.001
更新日期:2011-09-01 00:00:00
abstract::The reaction between cyanide and aurothiomalate (Autm) has been studied by 1H and 13C NMR spectroscopy and by uv spectroscopy. At cyanide:Autm ratios greater than or equal to 2, aurocyanide, [Au(CN)2]-, is the sole product but was also produced at lower ratios. Two intermediates were also identified. These were a mixe...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/0162-0134(85)80010-6
更新日期:1985-11-01 00:00:00
abstract::Classical molecular dynamic simulations and density functional theory are used to unveil the interaction of aluminum with various phosphorylated derivatives of the fragment KSPVPKSPVEEKG (NF13), a major multiphosphorylation domain of human neurofilament medium (NFM). Our calculations reveal the rich coordination chemi...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/j.jinorgbio.2020.111169
更新日期:2020-09-01 00:00:00
abstract::A pair of chiral binuclear ruthenium(II) complexes were prepared and their binding affinities towards double stranded native DNA were assessed by observing isotropic absorption, polarized light spectra - circular and linear dichroism (CD and LD), fluorescence quenching and DNA thermal denaturation. Upon binding to DNA...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/j.jinorgbio.2011.08.016
更新日期:2011-12-01 00:00:00
abstract::Iron overload can act as catalyst for the formation of free radicals, which may promote oxidant-mediated breast carcinogenesis. However, the association between iron and breast cancer has not been comprehensively elucidated. In this study, we found that iron overload upregulated the inflammatory cytokine interleukin-6...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/j.jinorgbio.2020.111159
更新日期:2020-09-01 00:00:00
abstract::In our previous studies, heme was bound into honeybee silk to generate materials that could function as nitric oxide sensors or as recoverable heterogeneous biocatalysts. In this study, we sought to increase the heme-binding capacity of the silk protein by firstly redesigning the heme binding site to contain histidine...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/j.jinorgbio.2017.08.031
更新日期:2017-12-01 00:00:00
abstract::The synthesis, crystal structures, physicochemical properties and complex formation constants of [Cu(phen)(2)(L)](ClO(4))(2) complexes, where phen is 1,10-ortho-phenanthroline and L is a series of substituted imidazolidine-2-thione, have been studied. Single crystal X-ray diffraction revealed a distorted trigonal-bipy...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/j.jinorgbio.2010.11.017
更新日期:2011-03-01 00:00:00
abstract::Industrial applications and environmental problems involving the aqueous chemistry of aluminium require an understanding of the speciation of this metal ion at a wide range of concentrations. The formation of polynuclear species is of special interest due to the complexity of the hydrolysis mechanisms and the diversit...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/s0162-0134(01)00326-9
更新日期:2001-11-01 00:00:00
abstract::The magnetic properties of intact and freeze-dried blood cells of the tunicate Ascidia nigra and of model vanadium(III) and (IV) compounds as polycrystalline solids and in aqueous solution have been measured up to 50 kOe with a SQUID susceptometer. Corrections for the samples' diamagnetism were extracted from the temp...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/0162-0134(88)80048-5
更新日期:1988-07-01 00:00:00
abstract::Raman spectra were acquired on ox femur samples treated with hydrazine to remove the organic components of bone. A large increase in the signal-noise ratio of the mineral spectrum resulted from the exposure of the mineral surface and the removal of fluorescent components of the organic matrix. The effect of hydrazine ...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/0162-0134(90)84002-7
更新日期:1990-07-01 00:00:00
abstract::It was shown that the treatment of a DNA fragment and a hepta-decanucleotide having a hairpin structure by Ru(2,2'-bipyridyl)3(3+) complex at 15 degrees C in 1 M NaCl for 10-60 min, and subsequent hydrolysis in 1 M piperidine at 95 degrees C led to the specific cleavage of the polynucleotide chain at guanosine residue...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/0162-0134(88)85025-6
更新日期:1988-11-01 00:00:00
abstract::Biological studies on [Fe(L)2](NO3).0.5H2O (1), [Fe(L)2][PF6] (2), [Co(L)2](NCS) (3), [Ni(HL)2]Cl2.3H2O (4) and Cu(L)(NO3) (5), where HL=C7H8N4S, pyridine-2-carbaldehyde thiosemicarbazone, have been carried out. The crystal structure of compound 3 has been solved. It consists of discrete monomeric cationic entities co...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/s0162-0134(01)00184-2
更新日期:2001-04-01 00:00:00
abstract::The pre-steady-state reduction of cytochrome P450 (P450) 2B4 by P450 reductase (reductase) was modeled by assuming that an equilibrium between three catalytic conformers of P450 regulates the multi-phasic reduction of the enzyme. This model was compared to a model of reduction involving a minimum number of phases. Bas...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/s0162-0134(03)00310-6
更新日期:2003-11-01 00:00:00
abstract::The clinical efficiency of Pt(II)-based drugs is founded on articulate mechanisms of action. Indeed it depends on a balanced combination of metal ion reactivity towards proteins and nucleic acids. Here we analysed the effect of two trans-platinum planar amines in comparison to cisplatin and transplatin on the DNA proc...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/j.jinorgbio.2020.111178
更新日期:2020-10-01 00:00:00
abstract::The CuA center is a dinuclear Cu2S2(Cys) electron transfer center found in cytochrome c oxidase and nitrous oxide reductase. In a previous investigation of the equatorial histidine ligands' effect on the reduction potential, electron transfer and spectroscopic properties of the CuA center, His120 in the engineered CuA...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/s0162-0134(99)00214-7
更新日期:2000-01-15 00:00:00
abstract::Complex formation between D-penicillamine (Pen) and copper(II) ions has been studied under simulated physiological conditions in both the presence and absence of the blood plasma constituents albumin, alanine, histidine, and zinc(II). Chromatographic and uv/vis and electron spin resonance (esr) spectroscopic methods w...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/s0162-0134(00)80020-3
更新日期:1979-11-01 00:00:00
abstract::We have studied the ground state of a realistic model of oxyheme with multiconfigurational second-order perturbation theory (CASPT2). Our results show that the ground-state electronic structure is strongly multiconfigurational in character. Thus, the wavefunction is a mixture of many different configurations, of which...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/j.jinorgbio.2004.11.008
更新日期:2005-01-01 00:00:00
abstract::Three biotinylated platinum(IV) complexes (1-3) were designed and synthesized. The resulting platinum(IV) complexes exhibited effective cytotoxicity against the tested cancer cell lines, especially complex 1, which was 2.0-9.6-fold more potent than cisplatin. These complexes were found to be rapidly reduced to their a...
journal_title:Journal of inorganic biochemistry
pub_type: 杂志文章
doi:10.1016/j.jinorgbio.2017.08.017
更新日期:2017-11-01 00:00:00