Abstract:
:Cryospectrokinetic studies of zinc and cobalt carboxypeptidase A disclosed two intermediates in the hydrolysis of both peptides and depsipeptides and furnished all the rate and equilibrium constants for the reaction scheme E + S in equilibrium ES1 in equilibrium ES2---E + P [Auld, D. S., Galdes, A., Geoghegan, K. F., Holmquist, B., Martinelli, R. A., & Vallee, B. L. (1984) Proc. Natl. Acad. Sci. U.S.A. 81, 5041-5045]. Since the ES2 intermediate is the predominate enzyme species present at steady state, its chemical nature is deducible from subzero chemical quench studies done after steady state is established. Extrapolation of the product concentration to zero time, [P0], measures the concentration of the enzyme species in which bond cleavage has occurred. For peptides, the [P0]values are zero, indicating that no product is generated prior to turnover and therefore the ES2 intermediate involves a complex between enzyme and intact peptide substrate. For depsipeptides, [P0] values are 1 mol of produce per mole of enzyme over the entire temperature range -20 to -50 degrees C, indicating cleavage of the ester bond occurs prior to the rate-limiting step so that ES2 is more properly denoted by EP1P2, where P1 and P2 are the substrates for the reverse reaction. The rate-limiting step for depsipeptides thus involves release of the products which may occur directly or through a mandatory conformational change followed by rapid product release.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Galdes A,Auld DS,Vallee BLdoi
10.1021/bi00351a020subject
Has Abstractpub_date
1986-02-11 00:00:00pages
646-51issue
3eissn
0006-2960issn
1520-4995journal_volume
25pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::Cytochrome bo from Escherichia coli is a ubiquinol oxidase which is a member of the superfamily of heme-copper respiratory oxidases. This superfamily, which includes the eukaryotic cytochrome c oxidases, has in common a bimetallic center consisting of a high-spin heme component and a copper atom (CuB) which is the sit...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00092a029
更新日期:1993-10-19 00:00:00
abstract::Chemical modification of Torpedo californica acetylcholinesterase by various sulfhydryl reagents results in its conversion to one of two principal states. One of these states, viz., that produced by disulfides and alkylating agents, is stable. The second state, produced by mercury derivatives, is metastable. At room t...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00252a006
更新日期:1994-12-06 00:00:00
abstract::We have previously shown that GTP can replace ATP as an energy source to support vinblastine transport by the multidrug transporter P-glycoprotein (Pgp) in plasma membrane vesicles isolated from the multidrug resistant cell line KB-V1 [Lelong et al. (1992) FEBS Lett. 304, 256-260]. Like [gamma-32P]ATP, [gamma-32P]GTP ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00196a009
更新日期:1994-08-02 00:00:00
abstract::Treatment of cells with the enediyne C-1027 is highly efficient at inducing single- and double-strand DNA breaks. This agent is highly cytotoxic when used at picomolar levels over a period of days. For this study, C-1027 has been used at higher levels for a much shorter time period to look at early cellular responses ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi015680c
更新日期:2001-12-04 00:00:00
abstract::The EcoRV DNA-(adenine-N6)-methyltransferase (MTase) recognizes GATATC sequences and modifies the first adenine residue within this site. Parts of its DNA interface show high sequence homology to DNA MTases of the dam family which recognize and modify GATC sequences. A phylogenetic analysis of M.EcoRV and dam-MTases s...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0155450
更新日期:2001-09-18 00:00:00
abstract::Structure-function studies of antibody-antigen systems include the identification of amino acid residues in the antigen that interact with an antibody and elucidation of their individual contributions to binding affinity. We used fluorescence correlation spectroscopy (FCS) and alanine-scanning mutagenesis to character...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0607047
更新日期:2006-11-28 00:00:00
abstract::Temperature-jump experiments were performed with di-, tetra-, and hexasaccharides derived from type III pneumococcal polysaccharide using a homogeneous corresponding antibody IgG 45-394. A decrease in stability of the oligosaccharide-antibody complexes with decreasing chain length was observed and entirely reflected i...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00637a023
更新日期:1977-09-06 00:00:00
abstract::S-Adenosylmethionine decarboxylase (AdoMetDC) is a key enzyme in the polyamine biosynthetic pathway. Inhibition of this pathway and subsequent depletion of polyamine levels is a viable strategy for cancer chemotherapy and for the treatment of parasitic diseases. Substrate analogue inhibitors display an absolute requir...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi900590m
更新日期:2009-07-14 00:00:00
abstract::The apolipoproteins of insect lipophorin were dissociated in guanidinium chloride and isolated by gel permeation chromatography. Over 98% of the total lipid in lipophorin was associated with apolipophorin I (apoLp-I), thus suggesting this apolipoprotein to be the lipid binding component of the particle. ApoLp-I was de...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00442a019
更新日期:1989-08-08 00:00:00
abstract::We have mapped the interface between the two transmembrane alpha-helices in the membrane domain of the Escherichia coli enzyme leader peptidase by analyzing disulfides formed between pairs of cysteine residues introduced near their respective periplasmic ends. The interface is formed primarily from aliphatic amino aci...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00084a020
更新日期:1993-08-24 00:00:00
abstract::We have expressed the alpha and beta subunits of bacterial luciferase, encoded by luxA and luxB, from separate plasmids in Escherichia coli and developed an efficient purification scheme that yields many milligrams of protein of greater than 90% homogeneity. Earlier experiments showed that subunits synthesized separat...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00070a010
更新日期:1993-05-18 00:00:00
abstract::The reactions of fully reduced and mixed-valence bovine heart cytochrome c oxidase with dioxygen have been reinvestigated in the absence and presence of metal ions (Zn(2+), Ni(2+), and Cd(2+)) by time-resolved optical absorption spectroscopy using the CO flow-flash technique. The time-resolved data were recorded on a ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi049408p
更新日期:2004-12-21 00:00:00
abstract::Extended-spectrum β-lactamases (ESBLs) pose a threat to public health because of their ability to confer resistance to extended-spectrum cephalosporins such as cefotaxime. The CTX-M β-lactamases are the most widespread ESBL enzymes among antibiotic resistant bacteria. Many of the active site residues are conserved bet...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi501195g
更新日期:2015-01-20 00:00:00
abstract::The specificity of valyl-, phenylalanyl-, and tyrosyl-tRNA synthetases from yeast has been examined by a series of stringent tests designed to eliminate the possibility of artefactual interference. Valyl-tRNA synthetase, as well as activating a number of amino acid analogues, will accept alanine, cysteine, isoleucine,...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00610a006
更新日期:1978-08-22 00:00:00
abstract::The EphA2 receptor plays key roles in many physiological and pathological events, including cancer. The process of receptor endocytosis and the consequent degradation have attracted attention as possible means of overcoming the negative outcomes of EphA2 in cancer cells and decreasing tumor malignancy. A recent study ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi300141h
更新日期:2012-03-13 00:00:00
abstract::B₁₂-dependent enzymes employ radical species with exceptional prowess to catalyze some of the most chemically challenging, thermodynamically unfavorable reactions. However, dealing with highly reactive intermediates is an extremely demanding task, requiring sophisticated control strategies to prevent unwanted side rea...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi500050k
更新日期:2014-06-17 00:00:00
abstract::A pressure-jump apparatus was employed in investigating the kinetics of protein unfolding and refolding. In the reaction cell, the pressure can be increased or decreased by 100-160 bar within 50-100 microseconds and then held constant. Thus, unfolding and refolding reactions in the time range from 70 microseconds to 7...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi982487i
更新日期:1999-03-09 00:00:00
abstract::Abortive transcription initiation can be rate-limiting for promoter escape and therefore represents a barrier to productive gene expression. The mechanism for abortive initiation is unknown, but the amount of abortive transcript is known to vary with the composition of the initial transcribed sequence (ITS). Here, we ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.5b00272
更新日期:2015-07-21 00:00:00
abstract::A method has been developed for calculating rate constants for dehydration of aldehydes that induce ATPase reactions by kinases and where 18O is transferred from the aldehyde or its hydrate to inorganic phosphate during the reaction. The method involves measurement of the fraction of 18O in phosphate by 31P NMR after ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00317a011
更新日期:1984-10-23 00:00:00
abstract::Mixed phospholipid systems of ether-linked 1,2-dihexadecylphosphatidylcholine (DHPC) and ester-linked 1,2-dipalmitoylphosphatidylcholine (DPPC) have been studied by differential scanning calorimetry and X-ray diffraction. At maximum hydration (60 wt % water), DHPC shows three reversible transitions: a main (chain melt...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00395a006
更新日期:1987-10-20 00:00:00
abstract::Ryanodine receptor (RyR) mutations linked with some congenital skeletal and cardiac diseases are localized to three easily definable regions: region 1 (N-terminal domain), region 2 (central domain), and a rather broad region 3 containing the channel pore. As shown in our recent studies, the interdomain interaction bet...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi061557f
更新日期:2007-04-10 00:00:00
abstract::Early studies involving purine salvage in Salmonella typhimurium resulted in the isolation and identification of a mutant strain possessing a genetically modified hypoxanthine phosphoribosyl-transferase (HPRT) with enhanced substrate specificity for guanine [Benson, C. E., and Gots, J. S. (1975) J. Bacteriol. 121, 77-...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9720179
更新日期:1998-03-10 00:00:00
abstract::Human liver alcohol dehydrogenase [alcohol:NAD+ oxidoreductase, EC 1.1.1.1 (ADH)] catalyzes the stereospecific oxidation of different 3 beta-hydroxy-5 beta-steroids with ranges of Km from 46 to 320 microM and values of kcat from 7.0 to 72 min-1, pH 8.5. Only the class I isozymes containing gamma-subunits, gamma 1 gamm...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00412a013
更新日期:1988-06-14 00:00:00
abstract::A previously unknown polypeptide myotoxin, designated myotoxin a, was isolated for the first time from prairie rattlesnake (Crotalus viridis viridis) venom. Electrophoretic homogeneity of myotoxin a was shown in beta-alanine disc gel polyacrylamide gel electrophoresis and in isoelectric focusing gel electrophoresis. M...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00630a035
更新日期:1977-05-31 00:00:00
abstract::Calmodulin and troponin C exhibit calcium-dependent binding of 1 mol/mol of dynorphin. The dissociation constants of the complexes, determined in 0.20 N KC1-1.0 mM CaCI2, pH 7.3, are 0.6 microM for calmodulin, 2.4 microM for rabbit fast skeletal muscle troponin C, and 9 microM for bovine heart troponin C. Experiments ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00306a016
更新日期:1984-05-22 00:00:00
abstract::Spectroscopic and kinetic methods have been used to explore the roles of divalent metal ions in the enolase-catalyzed dehydration of 2-phosphoglycerate (2-PGA). Enolase requires 2 equiv of metal ion per active site for maximal activity. Previous crystallographic studies [Larsen, T. M., Wedekind, J. E., Rayment, I., an...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0103922
更新日期:2001-07-10 00:00:00
abstract::A fluorescent derivative of lysine-258 isolated from the active site of aspartate aminotransferase modified by treatment of the apoenzyme with pyridoxal 5'-sulfate has been characterized as a substituted 2H-pyrrolo[3,4-c]pyridine. Similar pyrrolopyridines are produced in up to 20% yield by reaction of pyridoxal sulfat...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00264a016
更新日期:1982-10-12 00:00:00
abstract::We have characterized a membrane protein containing residues P688-T762 of the integrin beta3 subunit, encompassing its transmembrane and cytoplasmic domains, by nuclear magnetic resonance spectroscopy. Under conditions in which it is monomeric in dodecylphosphocholine micelles, the protein consists mainly of alpha-hel...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi026822l
更新日期:2002-12-31 00:00:00
abstract::The binding of propidium to poly(dA).poly(dT) [poly(dA.dT)] and to poly[d(A-T)].poly[d(A-T)] [poly[d(A-T)2]] has been compared under a variety of solution conditions by viscometric titrations, binding studies, and kinetic experiments. The binding of propidium to poly[d(A-T)2] is quite similar to its binding to calf th...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00336a029
更新日期:1985-07-16 00:00:00
abstract::The effect of DNA supercoiling on a sterically very demanding threading intercalation process is investigated here. We find that the threading rate of a dimeric ruthenium complex into a negatively supercoiled plasmid at low binding density is 2 orders of magnitude higher than into the cleaved linear form. Further satu...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi802336p
更新日期:2009-02-24 00:00:00