Abstract：
:Metabolism of [2-13C]-, [3-13C]-, and [1,2,3-13C]propionate in perfused rat livers and [2-13C]-acetate in perfused rat hearts has been examined in tissue extracts by 13C NMR. Label from [2-13C]-propionate was preferentially incorporated into the C2 carbon of lactate, alanine, and aspartate in liver tissue while label from [3-13C]propionate appeared preferentially in the C3 carbon of those same molecules. These data suggest that 13C may not be completely randomized in the symmetric citric acid cycle intermediates succinate and fumarate as is normally assumed but that some fraction of those intermediates may be transferred between enzymes in this span of the cycle with conservation of spatial orientation, consistent with recent results obtained in yeast [Sumegi et al. (1990) Biochemistry 29, 9106-9110]. This was confirmed by performing similar experiments with [1,2,3-13C]propionate. Time-dependent asymmetry was also observed between the intensities of the glutamate C2 and C3 resonances and between the aspartate C2 and C3 resonances in 13C NMR spectra of intact hearts and heart extracts during early perfusion with [2-13C]-acetate. A model is presented which predicts that isotopic asymmetry is observed only during the first 2-3 turns of the cycle pools when isotope enters the cycle via acetyl-CoA even if all symmetric cycle intermediates retain a unique molecular orientation on each pass through the citric acid cycle.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Sherry AD,Sumegi B,Miller B,Cottam GL,Gavva S,Jones JG,Malloy CRdoi
10.1021/bi00186a029subject
Has Abstractpub_date
1994-05-24 00:00:00pages
6268-75issue
20eissn
0006-2960issn
1520-4995journal_volume
33pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract：:The GTP-binding proteins or GTPases comprise a superfamily of proteins that provide molecular switches in numerous cellular processes. The "GTPase switch" paradigm, in which a GTPase acts as a bimodal switch that is turned "on" and "off" by external regulatory factors, has been used to interpret the regulatory mechani...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi9006989
更新日期：2009-07-28 00:00:00
abstract：:Some properties of [4-vinyl] chlorophyllide a reductase are described. This enzyme converts divinyl chlorophyllide a to monovinyl chlorophyllide a. The latter is the immediate precursor of monovinyl chlorophyll a, the main chlorophyll in green plants. [4-Vinyl] chlorophyllide a reductase plays an important role in day...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00151a011
更新日期：1992-09-15 00:00:00
abstract：:Scaffold/matrix-attached regions (S/MARs) are cis-acting elements with a function outside transcribed regions and in introns. Although they usually augment transcriptional rates, their action is highly context-dependent. We cloned an 800 bp S/MAR element from the upstream border of the human interferon-beta domain at ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi960930o
更新日期：1996-08-27 00:00:00
abstract：:Mutation of Pro94 to phenylalanine or alanine significantly alters the redox properties of the type I copper center of amicyanin. Each mutation increases the redox midpoint potential (E(m)) value by at least 140 mV and shifts the pK(a) for the pH dependence of the E(m) value to a more acidic value. Atomic resolution (...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi049634z
更新日期：2004-07-27 00:00:00
abstract：:The conformation of two fragments derived from anti-poly(D-alanyl) antibodies, the divalent fragment (Fab')2 and the monovalent fragment Fab', was studied by small-angle X-ray scattering before and after interaction with the tetra-D-alanine amide hapten. More than 90% of the combining sites were occupied by the hapten...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00677a035
更新日期：1975-03-25 00:00:00
abstract：:The transformation of DMPC vesicles containing myristic acid to larger structures was examined by nuclear magnetic resonance techniques. The process was found to be characterized by a rate which is approximately first order in vesicle concentration. Rates, however, show a dramatic increase with increasing myristic aci...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00610a027
更新日期：1978-08-22 00:00:00
abstract：:The Haemophilus influenzae diaminopimelate epimerase was cloned, expressed, purified, and crystallized in the C2221 space group (a = 102.1 A, b = 115.4 A, c = 66.3 A, alpha = beta = gamma = 90 degrees). The three-dimensional structure was solved to 2.7 A using a single Pt derivative and the Se-Met-substituted enzyme t...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi982138o
更新日期：1998-11-24 00:00:00
abstract：:To date, little work has been conducted on the relationship between solute and buffer molecules and conformational exchange motion in enzymes. This study uses solution NMR to examine the effects of phosphate, sulfate, and acetate in comparison to MES- and HEPES-buffered references on the chemical shift perturbation an...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi400973e
更新日期：2013-09-17 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：:Sf9 cells infected with a recombinant baculovirus containing the gene for human prorenin were cultured in the presence of [3H]mannose. In vivo labeled prorenin was isolated by immunoprecipitation from the culture medium and digested with Pronase. The oligosaccharide structures on the resulting glycopeptides were analy...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00195a022
更新日期：1994-07-26 00:00:00
abstract：:Rhodospirillum rubrum ribulose bisphosphate carboxylase contains two high affinity binding sites for pyridoxal phosphate and two catalytic sites per dimer. However, pyridoxal phosphate binding at only one site is sufficient for inactivation of both catalytic sites. In the presence of 20 mM bicarbonate, 10 mM magnesium...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00600a024
更新日期：1978-04-04 00:00:00
abstract：:Vanadate can often bind to phosphoryl transfer enzymes to form a trigonal-bipyramidal structure at the active site. The enzyme-vanadate dissociation constants in these enzymes are much lower than those for phosphate. Therefore, enzyme-bound vanadate moieties are often considered as transition state analogues. To test ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi016097z
更新日期：2002-05-07 00:00:00
abstract：:The interaction of fluorescent ATP analog 2'(3')-O-[N-[2-[3-(5-fluoresceinyl)thioureido]-ethyl]carbamoyl]adenosine 5'-triphosphate (FEDA-ATP) with rabbit skeletal myosin subfragment 1 (S1) and acto-S1 was studied. This and related ATP analogs are potentially useful for determination of the ATPase activity of single my...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi951824+
更新日期：1996-02-20 00:00:00
abstract：:A putative catalytic triad consisting of tyrosine, serine, and lysine residues was identified in the ketoreductase (KR) domains of modular polyketide synthases (PKSs) based on homology modeling to the short chain dehydrogenase/reductase (SDR) superfamily of enzymes. This was tested by constructing point mutations for ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi0268706
更新日期：2003-01-14 00:00:00
abstract：:The 270-MHz 1H nuclear magnetic resonance spectra of the apo, copper(I)-zinc(II), and copper(II)-zinc(II) forms of bovine erythrocyte superoxide dismutase (EC 1.15.1.1) are reported, and assignments of resonances to ten amino acid residues are proposed. The data require that at least four and probably six histidine re...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00633a003
更新日期：1977-07-12 00:00:00
abstract：:The behavior of photosystem II (PSII) reactions was investigated under conditions of decreasing water content by the addition of increasing concentrations of ethylene glycol (EG). The photosynthetic activities were measured for PSII samples either directly in aqueous solutions of EG or in the standard buffer medium fo...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi961724j
更新日期：1997-01-07 00:00:00
abstract：:The mechanism of herpesviral protease activation upon dimerization was studied using two independent spectroscopic assays augmented by directed mutagenesis. Spectroscopic changes, attributable to dimer interface conformational plasticity, were observed upon dimerization of Kaposi's sarcoma-associated herpesvirus prote...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi011753g
更新日期：2002-02-05 00:00:00
abstract：:High-resolution proton nuclear magnetic resonance (1H NMR) measurements were made on myosin, heavy meromyosin (HMM), myosin subfragment 1 (S1), light meromyosin (LMM), and actin. A strong signal from amino acid side chains undergoing motions too fast to be accounted for by simple rotations of groups on a rigid backbon...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00586a031
更新日期：1979-09-18 00:00:00
abstract：:The sequences and three-dimensional structures of the galactokinase, homoserine kinase, mevalonate kinase, and phosphomevalonate kinase (GHMP) family were compared to identify highly conserved surface residues. The functions of these solvent-accessible residues were assessed by determining the effects of their substit...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi048963o
更新日期：2004-11-23 00:00:00
abstract：:The mechanism by which the heme-containing peroxidase, chloroperoxidase, is able to chlorinate substrates is poorly understood. One approach to advance our understanding of the mechanism of the enzyme is to determine those factors which contribute to its stability. In particular, under alkaline conditions, chloroperox...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi961512m
更新日期：1996-11-19 00:00:00
abstract：:The interaction of proteoglycan monomers with hyaluronate in cartilage is mediated by a globular binding region at the N-terminus of the proteoglycan monomer; this interaction is stabilized by link protein. Sequences show that both the binding region (27% carbohydrate) and the link protein (6% carbohydrate) contain an...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00108a015
更新日期：1991-11-05 00:00:00
abstract：:G proteins play an important role in transmitting hormonal signals, and fluorescence techniques would be useful to study their cellular distribution and mechanisms. To prepare active fluorescent G protein Go/Gi or beta gamma subunits were reacted with fluorescein isothiocyanate (FITC) to label the alpha (F-alpha) and ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00060a035
更新日期：1993-03-09 00:00:00
abstract：:Cardiac troponin T (cTnT) is a myofibrillar protein essential for calcium-dependent contraction. This property has led to functional studies of developmentally expressed cTnT isoforms and mutants identified in patients with hypertrophic cardiomyopathy. The release of cTnT into the serum following myocardial infarction...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi7012596
更新日期：2008-02-19 00:00:00
abstract：:Human lysine demethylase KDM5A is a chromatin-modifying enzyme associated with transcriptional regulation, because of its ability to catalyze removal of methyl groups from methylated lysine 4 of histone H3 (H3K4me3). Amplification of KDM5A is observed in many cancers, including breast cancer, prostate cancer, hepatoce...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/acs.biochem.9b01036
更新日期：2020-02-11 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：:Activation of the zymogen form of a serine protease is associated with a conformational change that follows proteolysis at a specific site. Tissue-type plasminogen activator (t-PA) is homologous to mammalian serine proteases and contains an apparent activation cleavage site at arginine-275. To clarify the functional c...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00376a002
更新日期：1987-01-27 00:00:00
abstract：:Chemical modification and proteolytic digestion studies have identified a transmembrane glutamic acid residue (E953) of the alpha subunit of the pig kidney Na, K-ATPase as a possible cation binding site [Goldshleger et al. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 6911-6915]. In addition, an adjacent glutamate (E954) i...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00054a012
更新日期：1993-01-26 00:00:00
abstract：:PhnZ utilizes a mixed valence diiron(II/III) cofactor and O2 to oxidatively cleave the carbon-phosphorus bond of (R)-2-amino-1-hydroxyethylphosphonic acid to form glycine and orthophosphate. The active site residues Y24 and E27 are proposed to mediate induced-fit recognition of the substrate and access of O2 to one of...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/acs.biochem.9b00145
更新日期：2019-12-31 00:00:00
abstract：:Interconversion of protein conformations is imperative to function, as evidenced by conformational changes associated with enzyme catalytic cycles, ligand binding and post-translational modifications. In this study, we used 15N NMR relaxation experiments to probe the fast (i.e., ps-ns) and slow (i.e., micros-ms) confo...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi701425n
更新日期：2007-12-25 00:00:00
abstract：:Oligodeoxyribonucleotides cross-linked by reductively activated mitomycin C (MC) were prepared and purified for the first time. The cross-linked products were structurally characterized by nucleoside and MC-nucleoside adduct analysis. Optimal conditions were established for the cross-linking reaction, resulting in hig...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00464a015
更新日期：1990-03-27 00:00:00
