Abstract:
:Lipoprotein(a) [Lp(a)] is a unique lipoprotein consisting of a low-density lipoprotein moiety (LDL) covalently linked to apoprotein(a). Previous work has demonstrated that Lp(a) can compete with plasminogen (PGN) for binding to endothelial and mononuclear cells and can inhibit PGN activation in cell-free systems. We have assessed the binding of Lp(a) to platelets and the influence of binding on the activation of PGN by tissue-type plasminogen activator (t-PA) in this system. In direct binding experiments, Lp(a) bound specifically, saturably, and reversibly to platelets with an estimated apparent Kd of 0.20 microM. Scatchard analysis revealed a single class of binding sites with 81,000 +/- 22,000 particles of Lp(a) bound at saturation. Interestingly, Lp(a) bound to a similar extent to thromboasthenic platelets. Activation of platelets with ADP or thrombin reduced Lp(a) binding capacity by approximately 50% without changing affinity. Lp(a) also inhibited the binding of PGN to platelets with an IC50 of approximately 0.23 microM. Over a similar concentration range, LDL did not inhibit PGN binding to platelets. In addition, Lp(a) inhibited PGN binding to plasmin-treated platelets with an IC50 of approximately 0.2 microM. Kinetic experiments demonstrated that Lp(a) acted as a competitive inhibitor of PGN activation by t-PA on the platelet surface, with an estimated Ki of 0.49 microM. In the presence of platelets, Lp(a) decreased the kcat/Km for t-PA by 3-fold, owing primarily to an increase in the Km of t-PA for PGN. In contrast, LDL did not alter the kinetics of PGN activation by t-PA on the platelet surface.(ABSTRACT TRUNCATED AT 250 WORDS)
journal_name
Biochemistryjournal_title
Biochemistryauthors
Ezratty A,Simon DI,Loscalzo Jdoi
10.1021/bi00068a021subject
Has Abstractpub_date
1993-05-04 00:00:00pages
4628-33issue
17eissn
0006-2960issn
1520-4995journal_volume
32pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::trans-3-Chloroacrylic acid dehalogenase (CaaD) converts trans-3-chloroacrylic acid to malonate semialdehyde by the addition of H(2)O to the C-2, C-3 double bond, followed by the loss of HCl from the C-3 position. Sequence similarity between CaaD, an (alphabeta)(3) heterohexamer (molecular weight 47,547), and 4-oxalocr...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi030241u
更新日期:2004-04-13 00:00:00
abstract::Conceptually one may envisage that substrate binding sites on the ABC transporter P-gp cycle between high- and low-affinity conformations in response to signals arising from nucleotide hydrolysis to effect active transport. A radioligand binding assay was used to characterize the interaction of [3H]vinblastine with P-...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi011211z
更新日期:2001-12-25 00:00:00
abstract::Ferredoxin I from Desulfovibrio africanus (Da FdI) is a small acidic [4Fe-4S] cluster protein that exchanges electrons with pyruvate-ferredoxin oxidoreductase (PFOR), a key enzyme in the energy metabolism of anaerobes. The thermodynamic properties and the electron transfer between PFOR and either native or mutated FdI...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0485878
更新日期:2004-12-14 00:00:00
abstract::Recent results on the 102 residue protein U1A show that protein aggregation is not always slow and irreversible but may take place transiently in refolding studies on a millisecond time scale. In this study we observe a similar aggregation behavior with the classical two-state protein CI2. Since both U1A and CI2 appea...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9909997
更新日期:1999-10-05 00:00:00
abstract::Extracellular cAMP induces the rapid activation of guanylate cyclase, which adapts within 10 s to constant cAMP concentrations. A new response can be induced either by a higher cAMP concentration or by the same cAMP concentration at some time (t1/2 = 90 s) after removal of the previous stimulus. Stimulation of guanyla...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00397a047
更新日期:1987-11-17 00:00:00
abstract::Ketosteroid isomerase (KSI) is one of the most proficient enzymes catalyzing an allylic isomerization reaction at a diffusion-controlled rate. In this study of KSI, we have detailed the structures of its active site, the role of various catalytic residues, and have explained the origin of the its fast reactivity by ca...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi001629h
更新日期:2000-11-14 00:00:00
abstract::In the minor fraction of HDL3 containing alpha-tocopherol (alphaTocOH), selective one-electron oxidation of Trp and Tyr residues of apolipoproteins A-I and A-II by *Br2- radical-anions produces the corresponding semioxidized species, TyrO* and *Trp. Repair of TyrO* by endogenous alphaTocOH generates the alpha-tocopher...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi701419d
更新日期:2007-12-11 00:00:00
abstract::The stoichiometry of the nitrogenase ATP-dependent H2 evolution and ecetylene reduction reactions using S2O4(2-) as an electron source was studied by various techniques. For each mole of S2O4(2-) oxidized to 2SO3(2-) by the enzyme-catalyzed reactions at 25 degrees and pH 8, 1 mol of H2 (1 mol of ethylene for acetylene...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00690a019
更新日期:1975-09-23 00:00:00
abstract::In mesophiles, triosephosphate isomerase (TIM) is an obligated homodimer. We have previously shown that monomeric folding intermediates are common in the chemical unfolding of TIM, where dissociation provides 75% of the overall conformational stability of the dimer. However, analysis of the crystallographic structure ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi801360k
更新日期:2008-11-04 00:00:00
abstract::Natriuretic peptide receptor A (NPRA) is a noncovalent homodimeric receptor, composed of an extracellular domain (ECD) with a ligand-binding site, a single transmembrane domain (TM), and an intracellular domain (ICD) exhibiting guanylyl cyclase activity. NPRA activation by atrial natriuretic peptide (ANP) leads to cGM...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi901711w
更新日期:2010-06-08 00:00:00
abstract::The X-ray structures of neuronal nitric oxide synthase (nNOS) with N(omega)-hydroxy-l-arginine (l-NHA) and CO (or NO) bound have been determined at 1.91-2.2 A resolution. Microspectrophotometric techniques confirmed reduced redox state and the status of diatomic ligand complexes during X-ray diffraction data collectio...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9009743
更新日期:2009-11-03 00:00:00
abstract::The kinetics of self-association for beef liver glutamate dehydrogenase (EC 1.4.1.3) have been measured by using pressure perturbation in both the time domain and the frequency domain by monitoring scattered light intensity. The kinetic behavior is entirely consistent with the random self-association model proposed by...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00579a007
更新日期:1979-06-12 00:00:00
abstract::In this work we modeled the circular dichroism (CD) spectrum of LHCII, the main light harvesting antenna of photosystem II of higher plants. Excitonic calculations are performed for a monomeric subunit, taken from the crystal structure of trimeric LHCII from spinach [Liu, Z. F., Yan, H. C., Wang, K. B., Kuang, T. Y., ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi062031y
更新日期:2007-04-24 00:00:00
abstract::We found that recombinant human adult hemoglobin (rHb A) expressed in Escherichia coli showed heterogeneity of components with the intensity of a positive CD band at 260 nm and that it could be resolved into three components (SP-1, SP-2, and SP-3) by SP-Sepharose column chromatography. 1H NMR revealed that SP-1 is ide...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi7015519
更新日期:2008-01-15 00:00:00
abstract::Proteins have many distinct tertiary folds (Richardson, J. S. (1981) Adv. Prot. Chem. 34, 167-339). The term tertiary fold refers to the spatial organization of secondary structure elements (alpha-helices and beta-strands). It is not known when, in the process of protein folding, a native tertiary fold emerges. Here, ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00174a021
更新日期:1994-03-01 00:00:00
abstract::The properties of the homogeneous cutinase I, cutinase II, and the nonspecific esterase isolated from the extracellular fluid of cutin-grown Fusarium solani F. pisi (R.E. Purdy and P.E. Kolattukudy (1975), Biochemistry, preceding paper in this issue) were investigated. Using tritiated apple cutin as substrate, the two...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00684a007
更新日期:1975-07-01 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::Pulsed electron paramagnetic resonance spectroscopy has been used to detect Mn(II)-ligand superhyperfine couplings in complexes with creatine kinase and in the Mn(II) metalloprotein concanavalin A. Electron spin-echo envelopes from Mn(II), bound in these complexes, are modulated by superhyperfine interactions between ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00367a046
更新日期:1986-09-23 00:00:00
abstract::Biotin synthase (BioB) is an iron-sulfur dimeric enzyme which catalyzes the last step in biotin synthesis. The reaction consists of the introduction of a sulfur atom into dethiobiotin. It is shown here that BioB displays a significant cysteine desulfurase activity, providing it with the ability to mobilize sulfur from...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0122011
更新日期:2002-07-23 00:00:00
abstract::Acetylcholine receptors have been purified from junctional regions of normal rat diaphragm muscle and from extrajunctional regions of denervated diaphragm. The reaction of purified receptors with [122I]-alpha-bungarotoxin has been investigated by kinetic methods. The toxin-receptor complexes dissociated in a biphasic ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00681a008
更新日期:1975-05-20 00:00:00
abstract::Phosphorylation by ATP of E.*Ca2 (sarcoplasmic reticulum vesicles (SRV) with bound 45Ca2+) during 5-10 ms leads to the occlusion of 2 *Ca2+/EPtot [quench by ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) alone] in both "empty" (10 microM free Ca2+in) or "loaded" SRV (20-40 mM free Ca2+in)...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00408a041
更新日期:1988-04-19 00:00:00
abstract::Parathyroid hormone (PTH) regulates calcium and phosphate metabolism through a G-protein-coupled receptor which is shared with PTH-related protein (PTHrP). Therefore, structure-activity studies of PTH and PTHrP with their common receptor provide an unusual opportunity to examine the structural elements in the two horm...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00033a029
更新日期:1995-08-22 00:00:00
abstract::PKC phosphorylation regulates PITX2 DNA binding and transcriptional activity. Mutation of individual PKC sites demonstrates the functional regulation of PITX2 through phosphorylation. Immunoprecipitation of PITX2 and a PITX2 PKC mutant protein reveal specific in vivo phosphorylation by PKC in transfected cells. The tr...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi048362x
更新日期:2005-03-15 00:00:00
abstract::In order to more clearly define the structure of human plasma fibronectin (PFn) under physiologic buffer conditions, we determined the mean harmonic rotational relaxation times (rho H) of PFn and the thrombin-derived 190/170-kDa PFn fragment using steady-state fluorescence polarization. These measurements utilized the...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00464a027
更新日期:1990-03-27 00:00:00
abstract::We report here on the Raman spectra of NADH, 3-acetylpyridine adenine dinucleotide, APAD+, and a fragment of these molecules, adenosine 5'-diphosphate ribose (ADPR) bound to the mitochondrial (mMDH) and cytoplasmic (or soluble, sMDH) forms of malate dehydrogenase. We observe changes in the Raman spectrum of the adenos...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00100a011
更新日期:1991-09-10 00:00:00
abstract::Human liver aldehyde dehydrogenase isozymes E1 and E2 (EC 1.2.1.3) are both completely and irreversibly inactivated by bromoacetophenone (2-bromo-1-phenylethanone). Steady-state kinetics with both acetophenone and chloroacetophenone indicated interaction with the same enzyme form as the aldehyde substrate. Saturation ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00366a030
更新日期:1986-09-09 00:00:00
abstract::Chemical modification of mitochondrial F1-ATPase from Schizosaccharomyces pombe by the tryptophan-specific reagent N-bromosuccinimide (NBS) at pH 5.0 in the presence of 20% glycerol produced a characteristic lowering in both enzyme absorbance at 280 nm and intrinsic fluorescence at 332 nm that varied with NBS/F1 molar...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00055a004
更新日期:1993-02-02 00:00:00
abstract::Most RNA molecules that are endowed with catalytic activity function in the form of ribonucleoproteins within cells. These complexes are frequently large, poorly defined, and difficult to study. As a model system to study biological catalysis by ribonucleoproteins, we have modified the hairpin ribozyme by inserting an...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00023a021
更新日期:1995-06-13 00:00:00
abstract::Terminase is an enzyme from bacteriophage lambda that is required for insertion of the viral genome into an empty pro-capsid. This enzyme is composed of the viral proteins gpNu1 (20.4 kDa) and gpA (73.3 kDa) in a holoenzyme complex. Current models for terminase assembly onto DNA suggest that gpNu1 binds to three repea...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi981271d
更新日期:1999-01-05 00:00:00
abstract::The paralogues TRPV5 and TRPV6 belong to the vanilloid subfamily of the transient receptor potential (TRP) superfamily of ion channels, and both play an important role in overall Ca2+ homeostasis. The functioning of the channels centers on a tightly controlled Ca2+-dependent feedback mechanism in which the direct bind...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.7b01286
更新日期:2018-05-08 00:00:00