Abstract：
:The kinetic and thermodynamic features of reactions catalyzed by present-day enzymes appear to be the consequence of the evolution of these proteins toward maximal catalytic effectiveness. These features are identified and analyzed (in detail for one substrate-one product enzymes) by using ideas that link the energetics of the reaction catalyzed by an enzyme to the maximization of its catalytic efficiency. A catalytically optimized enzyme will have a value for the "internal" equilibrium constant (Kint, the equilibrium constant between the substrates and the products of the enzyme when all are bound productively) that depends on how close to equilibrium the enzyme maintains its reaction in vivo. Two classes are apparent. For an enzyme that operates near equilibrium, the catalytic efficiency is sensitive to the value of Kint, and the optimum value of Kint is near unity. For an enzyme that operates far from equilibrium, the catalytic efficiency is less sensitive to the value of Kint, and Kint assumes a value that ensures that the rate of the chemical transformation is equal to the rate of product release. In each of these cases, the internal thermodynamics is "dynamically matched", where the concentrations of substrate- and product-containing complexes are equal at the steady state in vivo.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Burbaum JJ,Raines RT,Albery WJ,Knowles JRdoi
10.1021/bi00450a009subject
Has Abstractpub_date
1989-11-28 00:00:00pages
9293-305issue
24eissn
0006-2960issn
1520-4995journal_volume
28pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract：:The importance of a specific hydrogen bond between thermolysin and a phosphonamidate inhibitor, Z-NHCH2-PO(O-)-Leu-Leu (1) [Bartlett, P. A., & Marlowe, C. K. (1987) Science (Washington D.C.) 235, 569-571], has been reevaluated. We have determined the inhibition constants (binding free energies) for thermolysin of phos...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00438a006
更新日期：1989-06-13 00:00:00
abstract：:High-affinity mu-conotoxin block of skeletal muscle Na+ channels depends on an arginine at position 13 (Arg-13). To understand both the mechanism of toxin interaction and the general structure of its binding site in the channel mouth, we examined by thermodynamic mutant cycle analysis the interaction between the criti...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi9724927
更新日期：1998-03-31 00:00:00
abstract：:Solvent proton nuclear magnetic dispersion studies at 25, 100, and 300 MHz have been performed on protocatechuate 3,4-dioxygenase (PCD) and its complexes with 3-chloro-4-hydroxybenzoate and 3-fluoro-4-hydroxybenzoate. Longitudinal and transverse relaxation rates were measured for these compounds and for the apoenzyme....
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00312a024
更新日期：1984-08-14 00:00:00
abstract：:Thermobifida fusca Cel9A-90, an unusual family 9 enzyme, is a processive endoglucanase containing a catalytic domain closely linked to a family 3c cellulose binding domain (Cel9A-68) followed by a fibronectin III-like domain and a family 2 cellulose binding domain. To study its catalytic mechanism, 12 mutant genes wit...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi049394n
更新日期：2004-08-03 00:00:00
abstract：:The functional role of distinct phospholipid subclasses and molecular species in modulating gramicidin-mediated K+ flux was characterized through quantification of changes in the fluorescence intensity of ion specific fluorescent probes encapsulated inside vesicles comprised of individual molecular species of plasmeny...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00022a008
更新日期：1995-06-06 00:00:00
abstract：:The phosphoryl-binding elements in the GDP-binding domain of elongation factor Tu were studied by heteronuclear proton observe methods. Five proton resonances were found below 10.5 ppm. Two of these were assigned to the amide groups of Lys 24 and Gly 83. These are conserved residues in each of the consensus sequences....
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00109a010
更新日期：1991-11-12 00:00:00
abstract：:Metal cations represent key elements of RNA structure and function. In the Neurospora VS ribozyme, metal cations play diverse roles; they are important for substrate recognition, formation of the active site, and shifting the pKa's of two key nucleobases that contribute to the general acid-base mechanism. Recently, we...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi401484a
更新日期：2014-01-28 00:00:00
abstract：:The di-heme enzyme MauG catalyzes the oxidative biosynthesis of a tryptophan tryptophylquinone cofactor on a precursor of the enzyme methylamine dehydrogenase (preMADH). Reaction of H2O2 with the diferric form of MauG, or reaction of O2 with diferrous MauG, forms the catalytic intermediate known as bis-Fe(IV), which a...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi401441h
更新日期：2013-12-31 00:00:00
abstract：:We investigated the effects of substituting two of the four tryptophans (the "inner pair" Trp(9) and Trp(11) or the "outer pair" Trp(13) and Trp(15)) in gramicidin A (gA) channels. The conformational preferences of the doubly substituted gA analogues were assessed using circular dichroism spectroscopy and size-exclusi...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi200136e
更新日期：2011-06-07 00:00:00
abstract：:The relaxin-like factor (RLF) is a circulating hormone that is synthesized in the gonads of mammals and released into the bloodstream. The distribution of its receptor and a trace of cross-reactivity to relaxin receptors implied that this relatively new factor is more relaxin- than insulin-like. The chemical synthesis...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi982687u
更新日期：1999-03-09 00:00:00
abstract：:Ala-based peptides form marginally stable helices at low temperature and are conventionally considered as mixtures of alpha-helix and random coil. However, recent work with doubly spin-labeled peptides suggests that short 16-residue sequences contain a significant fraction of 3(10)-helix near the N-terminus (positions...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00096a003
更新日期：1993-11-16 00:00:00
abstract：:A hairpin structure contains two conformationally distinct domains: a double-helical stem with Watson-Crick base pairs and a single-stranded loop that connects the two arms of the stem. By extensive 1D and 2D 500-MHz 1H NMR studies in H2O and D2O, it has been demonstrated that the DNA oligomers d(CGCCGCAGC) and d(CGCC...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00398a027
更新日期：1987-12-01 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：:Prokaryotic promoters have been extensively studied to relate sequence features to promoter function. Here we examine the relationship between double-helix stability and promoter activity. The double-helix stability is evaluated from sequence data by free energy computation, based on reported values of dinucleotide fr...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00414a035
更新日期：1988-07-12 00:00:00
abstract：:Recent studies have indicated that CYP3A4 exhibits non-Michaelis-Menten kinetics for numerous substrates. Both homo- and heterotropic activation have been reported, and kinetic models have suggested multiple substrates within the active site. We provide some of the first physicochemical data supporting the hypothesis ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi051689t
更新日期：2005-11-01 00:00:00
abstract：:In aqueous glycerol solutions, the rate constant for the formation of compound I of horseradish peroxidase from hydrogen peroxide is independent of the viscosity. However, whem m-chloroperbenzoic acid is used to form compound I, the rate is viscosity dependent, indicating that this reaction is diffusion controlled. Th...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00632a023
更新日期：1977-06-28 00:00:00
abstract：:Snake venom contains a number of the hemostatically active C-type lectin-like proteins, which affect the interaction between von Willebrand factor (vWF) and the platelet glycoprotein (GP) Ib or platelet receptor to inhibit/induce platelet activation. Flavocetin-A (FL-A) is a high-molecular mass C-type lectin-like prot...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi992134z
更新日期：2000-02-29 00:00:00
abstract：:The mechanism by which some hydrophobic molecules such as steroids and free fatty acids (FFA) act as noncompetitive inhibitors of the nicotinic acetylcholine receptor (AChR) is still not known. In the present work, we employ Förster resonance energy transfer (FRET) between the intrinsic fluorescence of membrane-bound ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi061388z
更新日期：2007-03-20 00:00:00
abstract：:Site-directed mutagenesis and high-resolution two-dimensional (2D) proton nuclear magnetic resonance (NMR) were used to probe the structural and functional roles of a highly conserved residue, Asp-49, in the interfacial catalysis by bovine pancreatic phospholipase A2 (PLA2, overexpressed in Escherichia coli). Accordin...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00253a009
更新日期：1994-12-13 00:00:00
abstract：:Highly purified tryptic fragments of calmodulin were tested for their ability to stimulate adenylate cyclase activity of Bordetella pertussis spheroplast membranes and were compared to their activities on brain Ca2+/calmodulin-dependent cyclic nucleotide phosphodiesterase. The C-terminal fragment, consisting of residu...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00372a025
更新日期：1986-12-02 00:00:00
abstract：:TOPORS is the first example of a protein that possesses both ubiquitin and SUMO E3 ligase activity. The ubiquitination activity maps to a conserved RING domain in the N-terminal region of the protein, which is not required for sumoylation activity. Similar to other E3 ligases, it is likely that the ubiquitin and sumoy...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi801904q
更新日期：2008-12-30 00:00:00
abstract：:Assignments have been made for 11 methyl, one Gln-C gamma, one Thr-C beta, and all six Tyr-C zeta carbon resonances of ribonuclease A. These partially serve to delineate the binding sites for Cu2+, Mn2+, phosphate, cytidine and its 2'-, 3'-, and 5'-phosphates (Cyd and Cyd-2'-P, -3'-P, and -5'-P), and one or a few urea...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00310a020
更新日期：1984-07-17 00:00:00
abstract：:Neuraminidase is one of the two glycoprotein spikes protruding from the influenza virus membrane. We have determined by X-ray crystallography the native structure of B/Lee/40 neuraminidase (NA) and the structures of its crystals soaked with a substrate, N-acetylneuraminyllactose (NANL), and an inhibitor, 2-deoxy-2,3-d...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00193a002
更新日期：1994-07-12 00:00:00
abstract：:Here we demonstrate that monovalent cations can localize around B-DNA in geometrically regular, sequence-specific sites in oligonucleotide crystals. Positions of monovalent ions were determined from high-resolution X-ray diffraction of DNA crystals grown in the presence of thallium(I) cations (Tl(+)). Tl(+) has previo...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi010391+
更新日期：2001-08-28 00:00:00
abstract：:Helix-helix interactions within membranes are dominated by van der Waals packing motifs and side chain-side chain hydrogen bond formation, which act in tandem to determine the residues that comprise the interface between two given helices. To explore in a systematic manner the tertiary contacts between transmembrane h...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi0492760
更新日期：2004-11-16 00:00:00
abstract：:While the urea-mediated unfolding pathway of the Escherichia coli aspartate aminotransferase (eAATase) homodimer proceeds through a reversible three-state process with a partially folded dimeric intermediate, D D* 2U (E. Deu and J. F. Kirsch, accompanying paper), that of a cofactor-stabilized form differs. Pyridoxal p...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi602632d
更新日期：2007-05-15 00:00:00
abstract：:Membrane vesicles can be prepared from murine lymphoid cells by nitrogen cavitation and fractionated by sedimentation through nonlinear sucrose density gradients. Two subpopulations of membrane vesicles, PMI and PMII, can be distinguished on the basis of sedimentation rate. The subcellular distribution of adenylate an...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00652a026
更新日期：1976-04-06 00:00:00
abstract：:The kinetics of folding/unfolding of cross-linked Lys7-dinitrophenylene-Lys41-ribonuclease A were studied and compared to those of unmodified ribonuclease A (RNase A) at various concentrations of guanidine hydrochloride. The folding of the denatured cross-linked protein involved one fast-folding species (22 +/- 4%) an...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00332a013
更新日期：1985-05-21 00:00:00
abstract：:The actin cytoskeleton carries out cellular functions, including division, migration, adhesion, and intracellular transport, that require a variety of actin binding proteins, including myosins. Our focus here is on class II nonmuscle myosin isoforms, NMIIA, NMIIB, and NMIIC, and their regulation by the actin binding p...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi500162z
更新日期：2014-06-24 00:00:00
abstract：:Although the binding of bivalent metal-ion activators to phosphoglucomutase produces substantial changes in the near ultraviolet spectrum of the enzyme, the extent to which aromatic residues are exposed to the aqueous environment, as assessed by means of solvent perturbation spectroscopy (using D2O), does not appear t...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00601a031
更新日期：1978-04-18 00:00:00
