Abstract:
:Klebsiella aerogenes urease uses a dinuclear nickel active site to catalyze the hydrolysis of urea. Here, we describe the steady-state and pre-steady-state kinetics of urease inhibition by fluoride. Urease is slowly inhibited by fluoride in both the presence and absence of substrate. Steady-state rate studies yield parallel double-reciprocal plots; however, we show that fluoride interaction with urease is not compatible with classical uncompetitive inhibition. Rather, we propose that fluoride binds to an enzyme state (E) that is in equilibrium with resting enzyme (E) and produced during catalysis. Fluoride binding rates are directly proportional to inhibitor concentration. Substrate reduces both the rate of fluoride binding to urease and the rate of fluoride dissociation from the complex, consistent with urea binding to E and E.F in addition to E. Fluoride inhibition is pH-dependent due to a protonation event linked to fluoride dissociation. Fluoride binding is pH-independent, suggesting that fluoride anion, not HF, is the actual inhibitor. We assess the kinetic results in terms of the known protein crystal structure and evaluate possible molecular interpretations for the structure of the E state, the site of fluoride binding, and the factors associated with fluoride release. Finally, we note that the apparent uncompetitive inhibition by fluoride as reported for several other metalloenzymes may need to be reinterpreted in terms of fluoride interaction with the corresponding E states.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Todd MJ,Hausinger RPdoi
10.1021/bi992287msubject
Has Abstractpub_date
2000-05-09 00:00:00pages
5389-96issue
18eissn
0006-2960issn
1520-4995pii
bi992287mjournal_volume
39pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::Seipin is a transmembrane protein that resides in the endoplasmic reticulum and concentrates at junctions between the ER and cytosolic lipid droplets. Mutations in the human seipin gene, including the missense mutation A212P, lead to congenital generalized lipodystrophy (CGL), characterized by the lack of normal adipo...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi1013003
更新日期:2010-12-21 00:00:00
abstract::Alpha-sarcin is an exquisitely specific ribonuclease that binds and cleaves a single phosphodiester bond in the large rRNA of the eukaryotic ribosome, inactivating it. To better understand this remarkable activity, the contributions of the active site residues (His 50, Glu 96, and His 137) to the conformational stabil...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi061273v
更新日期:2006-11-21 00:00:00
abstract::Troponin T (TnT) is an essential element in the thin filament-based regulatory system of striated muscle. Alternative mRNA splicing generates multiple TnT isoforms with primary structural differences in the NH2-terminal region. The functional significance of this hypervariable NH2-terminal domain and the developmental...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9812322
更新日期:1998-10-13 00:00:00
abstract::In circulation the phospholipid transfer protein (PLTP) facilitates the transfer of phospholipid-rich surface components from postlipolytic chylomicrons and very low density lipoproteins (VLDL) to HDL and thereby regulates plasma HDL levels. To study the molecular mechanisms involved in PLTP-mediated lipid transfer, w...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0621866
更新日期:2007-02-06 00:00:00
abstract::The mutagenic and genotoxic properties of 1,N6-ethenoadenine (epsilon Ade), 3,N4-ethenocytosine (epsilon Cyt), and 4-amino-5-(imidazol-2-yl)imidazole (beta) were investigated in vivo. The former two modified bases are known DNA adducts formed by the human carcinogen vinyl chloride; beta is formed by pyrimidine ring-op...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00210a031
更新日期:1993-11-30 00:00:00
abstract::Recently, we revealed the architecture of the clamp-loader-helicase (tau-DnaB) complex in Bacillus by atomic force microscopy imaging and constructed a structural model, whereby a pentameric clamp-loader interacts with the hexameric helicase. Crucial to this model is the assumption that the clamp-loader forms a pentam...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi034955g
更新日期:2003-09-23 00:00:00
abstract::Isoforms of transforming growth factor beta (TGFbeta) are 25 kDa homodimeric polypeptides that signal by binding and bringing together two related, functionally distinct cell surface receptors designated as TbetaR1 and TbetaR2. Here, we report the solution structure of the 13.8 kDa extracellular domain of human TbetaR...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi034366a
更新日期:2003-09-02 00:00:00
abstract::The tyrosine kinase c-Abl is implicated in a variety of cellular processes that are tightly regulated by c-Abl kinase activity and/or by interactions between c-Abl and other signaling molecules. The interaction of c-Abl with the Abl interactor protein Abi2 is shown to be negatively regulated by phosphorylation of seri...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi701533j
更新日期:2008-01-22 00:00:00
abstract::In order to more clearly define the structure of human plasma fibronectin (PFn) under physiologic buffer conditions, we determined the mean harmonic rotational relaxation times (rho H) of PFn and the thrombin-derived 190/170-kDa PFn fragment using steady-state fluorescence polarization. These measurements utilized the...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00464a027
更新日期:1990-03-27 00:00:00
abstract::The slowly hydrolyzed ATP analog adenosine 5'-(gamma-thiotriphosphate) (ATP gamma S) has been used in many studies of the muscle motor protein myosin in order to form a stable "weak binding" state analogous to the actin-S1-ATP complex However, the results from studies using ATP gamma S do not always agree with the res...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00049a018
更新日期:1995-12-12 00:00:00
abstract::Calcium trapped within sonicated and resealed bovine rod outer segment disks is released upon light exposure with a stoichiometry of 0.75 +/- 0.05 calcium for each rhodopsin bleached. The amount of calcium liberated is proportional to the amount of bleaching in the range of 20 to 100% bleaching and is relatively insen...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00626a025
更新日期:1977-04-05 00:00:00
abstract::The effect of pretreatment with sodium butyrate on DNA excision repair was studied in intact and permeable confluent (i.e., growth-inhibited) diploid human fibroblasts. Exposure to 20 mM sodium butyrate for 48 h increased subsequent ultraviolet (UV)-induced [methyl-3H]thymidine incorporation by intact AG1518 fibroblas...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00345a019
更新日期:1985-11-19 00:00:00
abstract::The initial step of infection of blood cells with the human immunodeficiency virus, HIV, is the formation of a complex of the viral envelope protein gp120 and its human receptor CD4. We have examined structural features of recombinant soluble CD4 (sCD4) by chemical modification of arginine residues with hydroxyphenylg...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi011626k
更新日期:2002-02-12 00:00:00
abstract::The l-lyxonate dehydratase (LyxD) in vitro enzymatic activity and in vivo metabolic function were assigned to members of an isofunctional family within the mandelate racemase (MR) subgroup of the enolase superfamily. This study combined in vitro and in vivo data to confirm that the dehydration of l-lyxonate is the bio...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi5004298
更新日期:2014-05-27 00:00:00
abstract::Many DNA polymerases select their natural substrates, deoxy- as opposed to ribonucleoside triphosphates, with a selectivity greater than 10000-fold. The function of a highly conserved residue, Tyr416, in the palm domain of the parental enzyme, an exo(-) derivative of RB69 DNA polymerase (gp43), a member of the pol alp...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0202171
更新日期:2002-08-13 00:00:00
abstract::We determined the effect of vertebrate albumins on the stability of several physiologically relevant prostaglandins. All naturally occurring prostaglandins with beta-hydroxy ketone group decomposed by first-order kinetics, dependent on the albumin concentration in 0.1 M, pH 7.4, buffer at 37 degrees C. Even subphysiol...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00524a033
更新日期:1981-10-13 00:00:00
abstract::The cellular site of formation, Galpha-coupling preference, and agonist regulation of mu-delta opioid receptor (OR) heterooligomers were studied. Bioluminescence resonance energy transfer (BRET) showed that mu-deltaOR heterooligomers, composed of preformed mu and delta homooligomers, interacted constitutively in the e...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi701436w
更新日期:2007-11-13 00:00:00
abstract::Although the mechanism by which the steroidogenic acute regulatory protein (StAR) promotes steroidogenesis has been studied extensively, it remains incompletely characterized. Because structural analysis has revealed a hydrophobic sterol-binding pocket (SBP) within StAR, this study sought to examine the regulatory rol...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi401125v
更新日期:2013-10-15 00:00:00
abstract::The interactions of Hoechst 33377 (H1) with 20 different oligomeric duplexes have been investigated via spectrofluorometric titrations and/or thermal denaturation experiments. H1 is shown to form 2:1 complexes with dsDNA binding sites of at least four contiguous A/T base pairs. H1 is also shown to possess the rare abi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0103415
更新日期:2001-05-29 00:00:00
abstract::UDP-glucose:glycoprotein glucosyltransferase (UGT) is a soluble protein of the endoplasmic reticulum (ER) that operates as a gatekeeper for quality control by preventing transport of improperly folded glycoproteins out of the ER. We report the isolation of two cDNAs encoding human UDP-glucose:glycoprotein glucosyltran...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9916473
更新日期:2000-03-07 00:00:00
abstract::Exons 1 and 2 and exon 8 of the mu class GSH transferases from rat encode sequence-variable regions 1 and 4 of mu class isoenzymes, respectively. These two of four variable regions are located at the N- and C-termini of this isoenzyme class and impinge on the active site. In order to assess the influence of these vari...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00157a005
更新日期:1992-10-27 00:00:00
abstract::The folding kinetics of a 16-residue beta-hairpin (trpzip4) and five mutants were studied by a laser-induced temperature-jump infrared method. Our results indicate that mutations which affect the strength of the hydrophobic cluster lead to a decrease in the thermal stability of the beta-hairpin, as a result of increas...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi052039s
更新日期:2006-02-28 00:00:00
abstract::Respiration, photosynthesis, and metabolism require the transfer of electrons through and between proteins over relatively long distances. It is critical that this electron transfer (ET) occur with specificity to avoid cellular damage, and at a rate that is sufficient to support the biological activity. A multistep ho...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi300817d
更新日期:2012-09-04 00:00:00
abstract::The importance of the interdomain bridging interactions observed only in the R-state structure of Escherichia coli aspartate transcarbamylase between Glu-50 of the carbamoyl phosphate domain with both Arg-167 and Arg-234 of the aspartate domain has been investigated by using site-specific mutagenesis. Two mutant versi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00458a015
更新日期:1990-02-13 00:00:00
abstract::By suspending bovine rhodopsin in trehalose-water glass films, it is possible to trap photostates in the light-activation process. Because of the unusually high vitrification temperature of trehalose-water mixtures, this trapping can be accomplished at room temperature. This allows for a facile investigation of the sp...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00181a004
更新日期:1994-04-19 00:00:00
abstract::Posttranslational glycosylation is critical for biological function of many proteins, but its structural characterization is complicated by natural heterogeneity, multiple glycosylation sites, and different forms. Here, a top-down mass spectrometry (MS) characterization is applied to three constructs of the Fc segment...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9919091
更新日期:2000-03-28 00:00:00
abstract::Synaptotagmin I is the calcium sensor in synchronous neurotransmitter release caused by fusion of synaptic vesicles with the presynaptic membrane in neurons. Synaptotagmin I interacts with acidic phospholipids, but also with soluble N-ethylmaleimide-sensitive factor attachment receptors (SNAREs), at various stages in ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi101864k
更新日期:2011-04-05 00:00:00
abstract::Faithful translation of the genetic code is mainly based on the specificity of tRNA aminoacylation catalyzed by aminoacyl-tRNA synthetases. These enzymes are comprised of a catalytic core and several appended domains. Bacterial glutamyl-tRNA synthetases (GluRS) contain five structural domains, the two distal ones inte...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi801690f
更新日期:2009-06-30 00:00:00
abstract::An important subject for elucidating membrane protein (MP) folding is how transmembrane helices (TMHs) insert into and dissociate from membranes. We investigated helix dissociation kinetics and insertion topology by means of intervesicular transfer of the fluorophore-labeled completely hydrophobic model transmembrane ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi026191v
更新日期:2002-10-15 00:00:00
abstract::A high molecular weight inert molecule, poly(ethylene glycol) (PEG), or a soluble protein, ovalbumin, causes parallel bundles of actin filaments in a crystalline-like structure under physiological conditions of ionic compositions and pH. The bundle formation depends on the molecular weight of PEG, and a larger molecul...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00441a052
更新日期:1989-07-25 00:00:00