Abstract:
:Methylmalonyl-CoA mutase from Propionibacterium shermanii is an adenosylcobalamin-dependent enzyme which catalyzes the reversible isomerization of methylmalonyl-CoA and succinyl-CoA. The rate of tritium loss from 5'-[3H]adenosylcobalamin during the enzymic reaction and the relative rates of tritium appearance in substrate and product were examined. Upon the addition of methylmalonyl-CoA to a solution of holoenzyme, tritium was completely released from the cofactor within about 500 ms. No tritium was found either bound to the enzyme or released into the water. The radioactivity was found in methylmalonyl-CoA and succinyl-CoA in a constant ratio of 1 to 3, which did not change during the first 300 ms of the reaction. Upon the addition of succinyl-CoA to a solution of holoenzyme, tritium was released at essentially the same rate, and the radioactivity was found in methylmalonyl-CoA and succinyl-CoA in the identical constant ratio of 1 to 3. The tritium isotope effect on the enzyme-catalyzed hydrogen transfer, measured using 14C-labeled methylmalonyl-CoA as substrate, was kH/kT = 4.9. This low value shows that hydrogen transfer is only partly rate limiting and that at least one subsequent slow step, such as product release, contributes substantially to the overall reaction velocity. The identical partitioning of tritium, regardless of the substrate used, shows that the rearrangement of the substrate radical into the product radical is not rate limiting. The very low tritium isotope effect and the fact that all the tritium is found bound either to the CoA esters or to the cofactor make it very unlikely that a protein radical is an intermediate in the methylmalonyl-CoA mutase-catalyzed rearrangement.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Meier TW,Thomä NH,Leadlay PFdoi
10.1021/bi961250osubject
Has Abstractpub_date
1996-09-10 00:00:00pages
11791-6issue
36eissn
0006-2960issn
1520-4995pii
bi961250ojournal_volume
35pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::Mouse photoreceptor function and survival critically depend on Ca(2+)-regulated retinal membrane guanylyl cyclase (RetGC), comprised of two isozymes, RetGC1 and RetGC2. We characterized the content, catalytic constants, and regulation of native RetGC1 and RetGC2 isozymes using mice lacking guanylyl cyclase activating ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi200491b
更新日期:2011-06-28 00:00:00
abstract::Group II introns self-splice via a two-step mechanism: cleavage at the 5' splice site followed by exon ligation at the 3' splice site. The second step has been difficult to study in vitro because it is generally faster than the first. Herein we describe development and partial kinetic characterization of a novel assay...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi000808w
更新日期:2000-08-22 00:00:00
abstract::A PS I membrane preparation from a PS II deficient mutant of Synechocystis sp. PCC 6803 (psb DI/DII/C) was investigated by picosecond photovoltage and fluorescence measurements. The photovoltage kinetics show two distinct phases. At low excitation energies the fast phase correlates with the fluorescence decay time con...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00195a001
更新日期:1994-07-26 00:00:00
abstract::4-Chlorobenzoyl-coenzyme A (4-CBA-CoA) dehalogenase catalyzes the hydrolysis of 4-CBA-CoA to 4-hydroxybenzoyl-coenzyme A (4-HBA-CoA) via a nucleophilic aromatic substitution pathway involving the participation of an active site carboxylate side chain in covalent catalysis. In this paper we report on the identification...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9609533
更新日期:1996-08-20 00:00:00
abstract::We have used nucleoside phosphorothioates (NTP alpha S) and a substitution-interference method to identify phosphate oxygens that appear to be important to guanosine cofactor addition in the self-splicing group I intron from Tetrahymena thermophila. For the majority of these phosphate oxygens, however, the effect of N...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00068a001
更新日期:1993-05-04 00:00:00
abstract::The tRNA(His) guanylyltransferase (Thg1) catalyzes the incorporation of a single guanosine residue at the -1 position (G(-1)) of tRNA(His), using an unusual 3'-5' nucleotidyl transfer reaction. Thg1 and Thg1 orthologs known as Thg1-like proteins (TLPs), which catalyze tRNA repair and editing, are the only known enzyme...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi201397f
更新日期:2012-01-10 00:00:00
abstract::This paper characterizes the low-affinity ligand binding interactions of a fluorinated volatile anesthetic, isoflurane (CHF2OCHClCF3), with bovine serum albumin (BSA) using 19F-NMR transverse relaxation (T2). 19F-NMR spectra of isoflurane in aqueous BSA reveal a single isoflurane trifluoromethyl resonance, indicative ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00146a007
更新日期:1992-08-11 00:00:00
abstract::The fidelity of the poliovirus RNA-dependent RNA polymerase (3D(pol)) plays a direct role in the genomic evolution and pathogenesis of the virus. A single site mutation (Gly64Ser) that is remote from the catalytic center results in a higher fidelity polymerase. NMR studies with [methyl-(13)C]methionine-labeled protein...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi100833r
更新日期:2010-11-02 00:00:00
abstract::The X-ray crystal structure of a salicylhydroxamic acid (SHA) inhibitory complex with human myeloperoxidase (MPO) has been determined at 2.3 A resolution. The aromatic ring of the inhibitor binds to a hydrophobic region at the entrance to the distal heme pocket between heme pyrrole ring D and the side chain of Arg 239...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi960577m
更新日期:1996-08-20 00:00:00
abstract::Protein kinase C-related kinases (PRKs) are serine/threonine kinases that are members of the protein kinase C superfamily and can be activated by binding to members of the Rho family of small G proteins via a Rho binding motif known as an HR1 domain. The PRKs contain three tandem HR1 domains at their N-termini. The st...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi200039u
更新日期:2011-04-12 00:00:00
abstract::Phototropin, a blue-light photoreceptor in plants, has two FMN-binding domains named LOV1 and LOV2. We previously observed temperature-dependent FTIR spectral changes in the C=O stretching region (amide-I vibrational region of the peptide backbone) for the LOV2 domain of Adiantum phytochrome3 (phy3-LOV2), suggesting p...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi061837v
更新日期:2006-12-26 00:00:00
abstract::The equilibrium between the rat brain tubulin alpha beta dimer and the dissociated alpha and beta monomers has been studied by analytical ultracentrifugation with use of a new method employing short solution columns, allowing rapid equilibration and hence short runs, minimizing tubulin decay. Simultaneous analysis of ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00228a023
更新日期:1991-04-09 00:00:00
abstract::The antibiotic bicyclomycin inhibits rho-dependent termination processes by interfering with RNA translocation by preventing RNA binding at the translocation site or by uncoupling the translocation process from ATP hydrolysis. Previous studies have shown that bicyclomycin binds near the ATP hydrolysis pocket on rho. T...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi000504+
更新日期:2000-08-08 00:00:00
abstract::We have characterized the importance of size, sulfation, and anticoagulant activity of heparin in release of basic fibroblast growth factor (bFGF) from the subendothelial extracellular matrix (ECM) and the luminal surface of the vascular endothelium. For this purpose, 125I-bFGF was first incubated with ECM and conflue...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00122a027
更新日期:1992-02-25 00:00:00
abstract::A 35-amino acid peptide corresponding to the putative "zinc finger" sequence of primase was prepared to study its zinc binding properties. When zinc was added to the peptide, it was found that the fluorescence quantum yield of the single tyrosine increased by 46% and the average lifetime by 34%. The binding stoichiome...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9612778
更新日期:1997-01-21 00:00:00
abstract::Efforts to characterize the receptor recognition domain of alpha-macroglobulins have primarily focused on human alpha 2-macroglobulin (alpha 2M). In the present work, the structure and function of the alpha-macroglobulin receptor recognition site were investigated by amino acid sequence analysis, plasma clearance, and...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00429a069
更新日期:1989-02-07 00:00:00
abstract::Surface-enhanced resonance Raman scattering (SERRS) spectra were obtained from carotenoids, in the all-trans configuration, located on the antenna complexes of Rhodobacter sphaeroides 2.4.1 membranes. Since resonance Raman (RR) spectra are barely detectable at the concentration that SERRS signals saturate, SERRS repre...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00455a017
更新日期:1990-01-23 00:00:00
abstract::The kinetics of reduction of free flavin semiquinones of the individual components of 1:1 covalent and electrostatic complexes of yeast ferric and ferryl cytochrome c peroxidase and ferric horse cytochrome c have been studied. Covalent cross-linking between the peroxidase and cytochrome c at low ionic strength results...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00406a029
更新日期:1988-03-22 00:00:00
abstract::A novel inhibitor of p38 mitogen-activated protein kinase (p38), CMPD1, identified by high-throughput screening, is characterized herein. Unlike the p38 inhibitors described previously, this inhibitor is substrate selective and noncompetitive with ATP. In steady-state kinetics experiments, CMPD1 was observed to preven...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0495073
更新日期:2004-09-21 00:00:00
abstract::The fidelity of DNA strand transfer reactions catalyzed by human immunodeficiency virus type 1 reverse transcriptase has been studied in vitro. A model system involving two sequential DNA strand transfers was developed to simulate the process of forced copy-choice recombination. A propensity for nucleotide misincorpor...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00179a014
更新日期:1994-04-05 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 binding of heparin to high molecular weight kininogen (H-kininogen) was analyzed by the effect of kininogen in decreasing the heparin-induced enhancement of the rate of inactivation of thrombin by antithrombin. The conditions were arranged so that the heparin-catalyzed antithrombin-thrombin reaction, monitored in ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00429a039
更新日期:1989-02-07 00:00:00
abstract::The following peptide was synthesized by classical methods in solution: Ac-Asp-Phe-Leu-Ala-Glu-Gly-Gly-Gly-Val-Arg-Gly-Pro-Arg-Val-NHCH3 (F-8). The Michaelis-Menten parameters for the hydrolysis of the Arg-Gly bond in F-8 by thrombin were determined to be Kcat = 31 X 10(-11) M [(NIH unit/L) s]-1 and KM = 310 X 10(-6) ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00287a002
更新日期:1983-08-30 00:00:00
abstract::One of the most promising approaches to anti-hepatitis C virus drug discovery is the development of inhibitors of the virally encoded protease NS3. This chymotrypsin-like serine protease is essential for the maturation of the viral polyprotein, and processing requires complex formation between NS3 and its cofactor NS4...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi991220w
更新日期:1999-10-19 00:00:00
abstract::We have determined the three-dimensional structure of a non-self-complementary oligodeoxynucleotide duplex that contains a model abasic site. The duplex contains six GC base pairs plus the abasic site at the center of one strand and corresponds to an abasic frameshift. Two-dimensional NMR studies on the nonexchangeabl...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00431a009
更新日期:1989-03-07 00:00:00
abstract::Pantothenate kinase (PanK) catalyzes the first step of the universal five-step coenzyme A (CoA) biosynthetic pathway. The recently characterized type III PanK (PanK-III, encoded by the coaX gene) is distinct in sequence, structure and enzymatic properties from both the long-known bacterial type I PanK (PanK-I, exempli...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi7018578
更新日期:2008-02-05 00:00:00
abstract::Glyoxylate carboligase (GCL) is a thiamin diphosphate (ThDP)-dependent enzyme, which catalyzes the decarboxylation of glyoxylate and ligation to a second molecule of glyoxylate to form tartronate semialdehyde (TSA). This enzyme is unique among ThDP enzymes in that it lacks a conserved glutamate near the N1' atom of Th...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi300893v
更新日期:2012-10-09 00:00:00
abstract::ATP and the fluorescent substrate analogue TNP-ATP bind competitively to the gastric H,-K-ATPase. Substrate and product completely reverse the fluorescence enhancement caused by TNP-ATP binding to the enzyme. The fluorophore is displaced monophasically from apoenzyme. However, ATP displaces TNP-ATP from the Mg2+-quenc...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00442a034
更新日期:1989-08-08 00:00:00
abstract::We have investigated in detail the cooperativity which we had previously observed in the pH titration profiles of the histidine residues of rabbit tropomyosin [Edwards, B. F. P., & Sykes, B. D. (1978) Biochemistry 17, 684]. Nonpolymerizing tropomyosin was prepared by carboxypeptidase digestion, and the titration profi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00517a037
更新日期:1981-07-07 00:00:00
abstract::A procedure has been developed to purify foot and mouth disease virus (FMDV) VP1 surface antigens from recombinant Escherichia coli. The VP1 antigens are expressed as fusion proteins derived from the E. coli Trp operon and VP1 surface protein of FMDV. The procedure is capable of recovering greater than 96% of the desi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00321a031
更新日期:1984-12-18 00:00:00