Abstract:
:The pH dependence of the transient aerobic kinetics of cytochromes c and a has been investigated with cytochrome oxidase reconstituted in phospholipid vesicles in the absence and presence of an uncoupler and an ionophore. The cytochrome a reduction level immediately after the burst phase was 60-80% and was not significantly changed by the addition of uncoupler and/or ionophore. The coupled rate of ferro-cytochrome c oxidation increases linearly with decreasing pH in the range 8.4-5.4. The increase in rate on uncoupling becomes less with decreasing pH and low cytochrome c concentration, being almost zero at pH 5.4. The coupled rate is increased by a lowering of the outside pH when the inside pH is constant. Varying the inside pH with a constant outside pH of 7.4 has little effect on the rate. It is suggested that the electrochemical potential has two separate effects on the coupled rate: the pH gradient mainly slows down the intramolecular electron transfer, but the membrane potential also lowers the second-order rate constant for the reaction with cytochrome c. The results are interpreted in terms of a model in which protonation of an acid-base group with a pKa of 6.4 from the inside increases the catalytic constant. Protonation from the outside, on the other hand, leads to an intrinsic uncoupling, because the protonated enzyme in the output state can return to the input state. This has no adverse physiological effect, since it becomes significant only at pH values well below 7.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Maison-Peteri B,Malmström BGdoi
10.1021/bi00434a007subject
Has Abstractpub_date
1989-04-18 00:00:00pages
3156-60issue
8eissn
0006-2960issn
1520-4995journal_volume
28pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::CDP-ribitol synthase is a bifunctional reductase and cytidylyltransferase that catalyzes the transformation of D-ribulose 5-phosphate, NADPH, and CTP to CDP-ribitol, a repeating unit present in the virulence-associated polysaccharide capsules of Haemophilus influenzae types a and b [Follens, A., et al. (1999) J. Bacte...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi002745n
更新日期:2001-04-24 00:00:00
abstract::The mechanism by which acyl-CoA dehydrogenases initiate catalysis was studied by using p-substituted phenylacetyl-CoAs (substituents-NO2, -CN, and CH3CO-), 3S-C8-, and 3'-dephospho-3S-C8CoA. These analogues lack a beta C-H and cannot undergo alpha,beta-dehydrogenation. Instead they deprotonate at alpha C-H at pH > or ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi971827h
更新日期:1998-02-17 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::Integrin conformational changes mediate integrin activation and signaling triggered by intracellular molecules or extracellular ligands. Even though it is known that αβ transmembrane domain separation is required for integrin signaling, it is still not clear how this signal is transmitted from the transmembrane domain...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi101462h
更新日期:2010-11-30 00:00:00
abstract::Phosphotriesterase, as isolated from Pseudomonas diminuta, is capable of detoxifying widely used pesticides such as paraoxon and parathion and various mammalian acetylcholinesterase inhibitors. The enzyme requires a binuclear metal center for activity. Recently, the three-dimensional structure of the apoenzyme was sol...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00025a002
更新日期:1995-06-27 00:00:00
abstract::The activation of adenosine-5'-monophosphate aminohydrolase from rabbit skeletal muscle by H+ has been demonstrated. Evidence is presented which indicates that the binding of H+ and K+ is linked, in that the dissociation constant (KA) for K+ activation is reduced as the pH is lowered. Concomitantly, the pK of several ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00641a013
更新日期:1977-11-01 00:00:00
abstract::The aminolysis of the depsipeptide m-[[(phenylacetyl)glycyl]oxy]benzoic acid (1) by D-phenylalanine, catalyzed by the beta-lactamase of Enterobacter cloacae P99, is inhibited by the product of the reaction, (phenylacetyl)glycyl-D-phenylalanine (2), by the peptide analogue of 1, m-[(phenylacetyl)-glycinamido]benzoic ac...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00443a015
更新日期:1989-08-22 00:00:00
abstract::ROS-GC represents a membrane guanylate cyclase subfamily whose distinctive feature is that it transduces diverse intracellularly generated Ca(2+) signals into the production of the second messenger cyclic GMP. An intriguing feature of the first subfamily member, ROS-GC1, is that it is both stimulated and inhibited by ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi990851n
更新日期:1999-09-28 00:00:00
abstract::The family 4 uracil-DNA glycosylase from the hyperthermophilic organism Archaeoglobus fulgidus (AFUDG) is responsible for the removal of uracil in DNA as the first step in the base excision repair (BER) pathway. AFUDG contains a large solvent-exposed peptide region containing an α helix and loop anchored on each end v...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi3000462
更新日期:2012-06-26 00:00:00
abstract::Molecular chaperones facilitate the folding and assembly of proteins and inhibit their aberrant aggregation. They thus offer several opportunities for biomedical and biotechnological applications, as for example they can often prevent protein aggregation more effectively than other therapeutic molecules, including sma...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.5b00459
更新日期:2015-08-18 00:00:00
abstract::Dynamic light scattering measurements were carried out on secretin in aqueous solution (2 mM; pH 5.0). The results indicated that the molecule exists as a fairly compact hexamer under these solution conditions. Secondary structural properties of the secretin hexameric complex were evaluated using CD and NMR spectrosco...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi980701x
更新日期:1998-12-01 00:00:00
abstract::The structure of a synthetic peptide corresponding to residues 1-45 of rabbit muscle adenylate kinase has been studied in aqueous solution by two-dimensional NMR, FTIR, and CD spectroscopy. This peptide, which binds MgATP and is believed to represent most of the MgATP-binding site of the enzyme [Fry, D.C., Kuby, S.A.,...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00410a009
更新日期:1988-05-17 00:00:00
abstract::Pokeweed antiviral protein (PAP) is a ribosome inactivating protein (RIP) that depurinates the sarcin/ricin loop (SRL) of rRNA, inhibiting protein synthesis. PAP depurinates viral RNA, and in doing so, lowers the infectivity of many plant viruses. The mechanism by which PAP accesses uncapped viral RNA is not known, im...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.7b00598
更新日期:2017-11-14 00:00:00
abstract::Yeast actin mutants with acidic residues at the N terminus either neutralized (DNEQ) or deleted (delta-DSE) were used to assess the role of N-terminal acidic residues in the interactions of actin with myosin in the contractile cycle. Cosedimentation experiments revealed an approximately 3-fold decrease in the binding ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi962388+
更新日期:1996-12-24 00:00:00
abstract::Spectrin dimers interact weakly with F-actin under physiological solvent conditions (with an association constant of about 5 X 10(3) M-1 at 20 degrees C). In the presence of the membrane skeletal constituent, protein 4.1, strong binding is observed; an analysis of the profiles for formation of a ternary complex leads ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00314a027
更新日期:1984-09-11 00:00:00
abstract::Three spin-labeled derivatives of the voltage-gated peptide alamethicin were prepared with nitroxides at the C-terminal phenyalaninol, and at positions 9 and 15 in the amino acid sequence. In addition, three spin-labeled derivatives of an analog of alamethicin where alpha-methylalanine residues are replaced by leucine...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi951985d
更新日期:1996-01-16 00:00:00
abstract::Transcarboxylase (TC) from Propionibacterium shermanii, a biotin-dependent enzyme, catalyzes the transfer of a carboxyl group from methylmalonyl-CoA to pyruvate to form propionyl-CoA and oxalacetate. Within the multi-subunit enzyme complex, the 1.3S subunit functions as the carboxyl group carrier and also binds the ot...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9925367
更新日期:2000-03-14 00:00:00
abstract::The light-driven enzyme NADPH:protochlorophyllide oxidoreductase (POR) catalyzes the reduction of protochlorophyllide (Pchlide) to chlorophyllide (Chlide), a key regulatory step in the chlorophyll biosynthesis pathway. As POR is light activated, it allows intermediates in the reaction pathway to be observed by initiat...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0268448
更新日期:2003-01-21 00:00:00
abstract::The crystal structure of a cytochrome P450 from the thermoacidophile Picrophilus torridus, CYP231A2 (PTO1399), has been solved. This structure reveals a wide open substrate access channel. To better understand ligand-induced structural transitions in CYP231A2, protein-ligand interactions were investigated using 4-phen...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi702240k
更新日期:2008-02-19 00:00:00
abstract::The structure of a 22 amino acid peptide, TPPI [Nedved, M. L., Gottlieb, P. A., & Moe, G. R. (1994) Nucleic Acids Res. 22, 5024-5030], that is similar to the proline repeat segment of the replication arrest protein, Tus, has been determined by 1H NMR in 50% trifluroethanol. The structure is a novel left-handed helix h...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi952419l
更新日期:1996-01-23 00:00:00
abstract::The mitochondrial folate transporter (MFT) was previously identified in human and hamster cells. Sequence homology of this protein with the inner mitochondrial membrane transporters suggested a domain structure in which the N- and C-termini of the protein are located on the mitochondrial intermembrane-facing surface, ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi062191+
更新日期:2007-02-13 00:00:00
abstract::The solution structure of the dicerium(III) complex of the N-terminal domain of calmodulin (Ce2-TR1C hereafter) has been solved employing paramagnetic T1 relaxation enhancements and pseudocontact shifts introduced by the Ce3+ ions, together with conventional NOE constraints. The use of pseudocontact shift constraints ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi971022+
更新日期:1997-09-30 00:00:00
abstract::We report on the determination of the solution structure of two sequence-related oligonucleotides, d(GTACGTAC)2 and d(CATCGATG)2. Results have been obtained by using a combined approach of (a) two-dimensional NMR, including proton and phosphorus experiments, (b) restrained molecular mechanics performed with sugar phas...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00037a045
更新日期:1995-09-19 00:00:00
abstract::Transcription of the human nonmuscle myosin II heavy chain-A (NMHC-A) gene is regulated via multiple elements located in intron 1, including element F which contains an E-box. In this study we have identified and characterized the factors that are capable of binding to element F. Yeast one-hybrid screening using eleme...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi002847d
更新日期:2001-07-31 00:00:00
abstract::To identify interactions between Ste2p, a G protein-coupled receptor of the yeast Saccharomyces cerevisiae, and its tridecapeptide ligand, alpha-factor (WHWLQLKPGQPMY), a variety of alpha-factor analogues were used in conjunction with site-directed mutagenesis of a targeted portion of Ste2p transmembrane domain six. A...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi026100u
更新日期:2002-11-19 00:00:00
abstract::A small metal-binding protein (SmbP) with no known similarity to other proteins in current databases was isolated and characterized from the periplasm of Nitrosomonas europaea. The primary structure of this small (9.9 kDa) monomeric protein is characterized by a series of 10 repeats of a seven amino acid motif and an ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi049318k
更新日期:2004-09-07 00:00:00
abstract::Human granulocyte chemotactic protein 2 (GCP-2) has originally been isolated from cytokine-stimulated osteosarcoma cells as a chemokine coproduced in minute amounts together with interleukin 8. Human GCP-2 (75 residues) was synthesized on a 0.25-mmol scale using Fmoc chemistry. After disulfide bridge formation and pur...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi961999z
更新日期:1997-03-04 00:00:00
abstract::A detailed characterization of the main chain and side chain dynamics in R. capsulatus ferrocytochrome c(2) derived from (2)H NMR relaxation of methyl group resonances is presented. (15)N relaxation measurements confirm earlier results indicating that R. capsulatus ferrocytochrome c(2) exhibits minor rotational anisot...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0102252
更新日期:2001-06-05 00:00:00
abstract::Identical first-order rate constants for phosphorylation of the calcium ATPase of sarcoplasmic reticulum by bound inorganic phosphate (Pi) of 25 +/- 2 s-1 with empty vesicles and 25 +/- 1 s-1 with vesicles that were passively loaded with 40 mM Ca2+ were obtained by treating the reaction as an approach to equilibrium (...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00009a039
更新日期:1995-03-07 00:00:00
abstract::The binding of the inhibitor 8-nitroxanthine to urate oxidase has been investigated by Raman and UV-visible absorption spectroscopy. The absorption maximum of 8-nitroxanthine shifts from 380 to 400 nm upon binding to the enzyme, demonstrating that the electronic structure of the ligand is perturbed. It has been propos...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0507837
更新日期:2005-08-30 00:00:00