Abstract：
:Leucine aminopeptidase (LAP) is a protease requiring two divalent metal cations per subunit for activity. Zn2+, Mg2+, and Co2+ metal-substituted forms of LAP have been prepared and investigated kinetically. Substitution of metal into the two binding sites independently resulted in the preparation of Zn2+Zn2+, Mg2+Zn2+, Co2+Co2+, Zn2+Co2+, Mg2+Co2+, and Co2+Zn2+ LAP derivatives that were characterized by atomic absorption spectrophotometry. Kinetic analysis of the metal-substituted enzymes indicated that site 1 (fast exchanging) metal substitution results in a Km decrease in the relative order Zn2+ greater than Mg2+ greater than Co2+. Similar comparisons for the site 2 metal (slow exchanging) involved only Zn2+ and Co2+, since only these metals have been shown to compete effectively for this site. Substitution of these two metals into site 2 revealed a Km decrease in the order Zn2+ greater than Co2+. It was suggested previously [e.g., Thompson, G. A., & Carpenter, F. H. (1976) J. Biol. Chem. 251, 1618-1624] that the fast-exchanging site 1 metal predominantly effects kcat while the slow-exchanging metal in site 2 exerts effects exclusively on Km. The present study, the first direct comparison of Km change resulting from metal substitution into both sites, clearly indicates that both metal sites exert significant effects on Km. In addition, the data suggest a more complex interaction between the two bound metals than previously suspected.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Allen MP,Yamada AH,Carpenter FHdoi
10.1021/bi00285a010subject
Has Abstractpub_date
1983-08-02 00:00:00pages
3778-83issue
16eissn
0006-2960issn
1520-4995journal_volume
22pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract：:The electrons extracted from the CaMn(4) cluster during water oxidation in photosystem II are transferred to P(680)(+) via the redox-active tyrosine D1-Tyr161 (Y(Z)). Upon Y(Z) oxidation a proton moves in a hydrogen bond toward D1-His190 (His(Z)). The deprotonation and reprotonation mechanism of Y(Z)-OH/Y(Z)-O is of k...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi101364t
更新日期：2010-11-16 00:00:00
abstract：:The three-dimensional chalice-like crystal structure of initiation factor 2 IF2/eIF5B from Methanobacterium thermoautotrophicum represents a novel fold and domain architecture in which the N-terminal G domain and the C-terminal C domain are separated by an approximately 40 A alpha-helix. Homologous Thermus thermophilu...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi702295g
更新日期：2008-04-29 00:00:00
abstract：:kappa-Bungarotoxin (kappa-bgt) is a 66-residue peptide originally purified from snake venom that acts as an antagonist at certain acetylcholine receptors. It is one of four homologous kappa-neurotoxins that are distinguished from the structurally related alpha-neurotoxins by their ability to block the alpha 3-subunit-...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00248a004
更新日期：1994-11-08 00:00:00
abstract：:In prokaryotes, the first three enzymes in pyrimidine biosynthesis, carbamoyl phosphate synthetase (CPS), aspartate transcarbamoylase (ATC), and dihydroorotase (DHO), are commonly expressed separately and either function independently (Escherichia coli) or associate into multifunctional complexes (Aquifex aeolicus). I...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi801831r
更新日期：2009-02-03 00:00:00
abstract：:Studies are presented of the equilibrium binding of [3H]-d-tubocurarine (dTC) and [3H]acetylcholine (AcCh) to Torpedo postsynaptic membranes. The saturable binding of [3H]dTC is characterized by two affinities: Kd1 = 33 +/- 6 nM and Kd2 = 7.7 +/- 4.6 microM, with equal numbers of binding sites. Both components are com...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00591a032
更新日期：1979-11-27 00:00:00
abstract：:A stereochemical analysis has been carried out on two vinylpyruvate hydratases (VPH), which convert 2-hydroxy-2,4-pentadienoate to 2-keto-4S-hydroxypentanoate in meta-fission pathways. Bacterial strains with this pathway can use aromatic compounds as sole sources of energy and carbon. The analysis was carried out usin...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/acs.biochem.6b00552
更新日期：2016-07-26 00:00:00
abstract：:Glutaraldehyde treatment of electroplax membrane preparations of Na,K-ATPase leads to irreversible changes in the enzymic behavior of the protein, which are not due to modification of the active site. When the glutaraldehyde treatment is carried out in a medium containing K+ and without Na+, the "K+-modified enzyme" s...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00288a016
更新日期：1983-09-13 00:00:00
abstract：:Steroid-receptor complexes formed at low temperature and ionic strength are unable to bind to target cell nuclei. After a temporary exposure to high ionic strength and/or temperature they become activated (i.e., able to bind to nuclei). However, there exists an equilibrium between activated and nonactivated complexes;...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00664a025
更新日期：1976-09-21 00:00:00
abstract：:The heme binding sites of rabbit histidine-rich glycoprotein (HRG), 94 kDa, were studied with rose bengal (RB), a fluorescein derivative that associates with histidine residues. Difference absorbance spectra indicate that HRG binds RB at two thermodynamically preferred sites (Kd approximately 2 microM) that are spectr...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00342a034
更新日期：1985-10-08 00:00:00
abstract：:In this study, we investigated the role of ubiquitination in the disposition of the inactivated O6-methylguanine-DNA methyltransferase (MGMT) protein in human (HT-29 and CEM) and murine (ts85) tumor cells. Using a combination of immunoprecipitation and immunoblotting techniques with antibodies against ubiquitin and MG...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi9518205
更新日期：1996-01-30 00:00:00
abstract：:Endothelium-derived epoxyeicosatrienoic acids (EETs) relax vascular smooth muscle by activating potassium channels and causing membrane hyperpolarization. Recent evidence suggests that EETs act via a membrane binding site or receptor. To further characterize this binding site or receptor, we synthesized 20-iodo-14,15-...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi102070w
更新日期：2011-05-10 00:00:00
abstract：:The three-dimensional structure of the fatty-acid-binding protein isolated from the flight muscle of the desert locust Schistocerca gregaria has been solved and refined to a crystallographic R-value of 18.5% for all measured X-ray data from 30.0- to 2.2-A resolution. Crystals employed in the investigation were grown f...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00207a004
更新日期：1994-10-18 00:00:00
abstract：:The mechanism of binding of the substrates Mg x ATP and ribose 5-phosphate as well as Mg2+ to the enzyme 5-phospho-D-ribosyl (alpha-1-diphosphate synthetase from Escherichia coli has been analyzed. By use of the competive inhibitors of ATP and ribose 5-phosphate binding, alpha,beta-methylene ATP and (+)-1-alpha,2-alph...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi962610a
更新日期：1997-04-22 00:00:00
abstract：:Exposure of mammalian cells (transformed mouse fibroblasts or rat hepatoma cells) to S-adenosyl-1,8-diamino-3-thiooctane produced profound changes in the intracellular polyamine content. Putrescine was increased and spermidine was decreased, consistent with the inhibition of spermidine synthase by this compound, which...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00263a036
更新日期：1982-09-28 00:00:00
abstract：:A new strategy to form stable and sequence-specific triple helical DNA structures at mixed purine/pyrimidine sequences using a combination of four C-glycosides (TRIPsides) has been described [Li et al. (2003) J. Am. Chem. Soc. 125, 2084]. The partial realization of the approach is demonstrated by incorporating two of ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi035648d
更新日期：2004-02-17 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：:Bacteriophage P22 is a double-stranded DNA containing phage. Its morphogenetic pathway requires the formation of a precursor procapsid that subsequently matures to the capsid. The stability of bacteriophage P22 coat protein in both monomeric and polymeric forms under hydrostatic pressure has been examined previously [...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00004a003
更新日期：1995-01-31 00:00:00
abstract：:Orthophosphate and phosphate derivatives including pyrophosphate, hexametaphosphate, ATP, ADP, and inositol hexaphosphate enhance the extent of DNA degradation by iron(II) bleomycin. These phosphate-containing compounds increase both the release of free nucleic base and that of base propenals which are DNA cleavage pr...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00335a034
更新日期：1985-07-02 00:00:00
abstract：:The amidotransferase family of enzymes utilizes the ammonia derived from the hydrolysis of glutamine for a subsequent chemical reaction catalyzed by the same enzyme. The ammonia intermediate does not dissociate into solution during the chemical transformations. A well-characterized example of the structure and mechani...
journal_title：Biochemistry
pub_type： 杂志文章,评审
doi：10.1021/bi990871p
更新日期：1999-06-22 00:00:00
abstract：:The sialic acid N-acetylneuraminic acid (NANA) has a key role in the pathogenesis of a select number of neuroinvasive bacteria such as Neisseria meningitidis. These pathogens coat themselves with polysialic acids, mimicking the exterior surface of mammalian cells and consequentially concealing the bacteria from the ho...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi400062c
更新日期：2013-04-16 00:00:00
abstract：:We have examined the C cluster in type II CO dehydrogenase (CODH) from Carboxydothermus hydrogenformans using Ni K-edge X-ray absorption near edge spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy. The enzyme was studied under three conditions: "as-isolated" and after treatment with CO or ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi036104e
更新日期：2004-07-20 00:00:00
abstract：:We describe the synthesis of bordifluoropyrromethene (BODIPY), fluorescein, and related fluorescent derivatives of the beta-adrenergic ligand CGP 12177. With these probes we screened insect (Sf9) cells stably transformed with the human beta 2-adrenoceptor gene and expressing (2-3.5) x 10(5) human beta 2-adrenoceptors ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00197a015
更新日期：1994-08-09 00:00:00
abstract：:c-Myc is a member of a family of sequence specific-DNA binding proteins that are thought to regulate the transcription of genes involved in normal cell growth, differentiation, and apoptosis. In order to understand how human c-myc functions as a transcription factor, we have studied the mechanism of action and structu...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi960793v
更新日期：1996-07-23 00:00:00
abstract：:Backbone amide dynamics of the Escherichia coli tryptophan repressor protein (WT-TrpR) and two functionally distinct variants, L75F-TrpR and A77V-TrpR, in their holo (l-tryptophan corepressor-bound) form have been characterized using (15)N nuclear magnetic resonance (NMR) relaxation. The three proteins possess very si...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi200389k
更新日期：2011-06-14 00:00:00
abstract：:The EP3 subtype of prostaglandin E2 receptor transduces diverse physiological responses in mammalian tissues through signaling pathways coupled to heterotrimeric G proteins. Distinct cDNA clones encoding five isoforms of the EP3 receptor were isolated from a human uterus cDNA library. The human EP3 receptor isoforms d...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00252a016
更新日期：1994-12-06 00:00:00
abstract：:X-ray diffraction measurements show that in contrast to the purple membrane, the bacteriorhodopsin molecules are not organized in a hexagonal lattice in the deionized blue membrane. Addition of Ca2+ restores both the purple color and the normal (63 A) hexagonal protein lattice. In the blue state, the circular dichrois...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00449a031
更新日期：1989-11-14 00:00:00
abstract：:Interactions of the beta subunit of the Oxytricha nova telomere binding protein with the telomeric DNA sequences, d(T4G4)2 and dT6(T4G4)2, have been investigated in vitro using Raman and fluorescence spectroscopies. Raman difference spectra show that the beta subunit binds to both d(T4G4)2 and dT6(T4G4)2 but promotes ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi972400d
更新日期：1998-02-03 00:00:00
abstract：:Factors determining conformations of imidazole axially coordinated to heme in heme proteins were investigated by analyzing 693 hemes in 432 different crystal structures of heme proteins from the Protein Data Bank (PDB), where at least one histidine is ligated to heme. The results from a search of the PDB for protein s...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi010428q
更新日期：2001-07-03 00:00:00
abstract：:The light-induced QA-/QA FTIR difference spectrum of the photoreduction of the primary quinone (QA) in reaction centers (RCs) from Rhodobacter sphaeroides exhibits a set of complex differential bands between 1750 and 1715 cm(-1). Several of these features correspond in frequency to bands that bleach in the HA-/HA FTIR...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi962871k
更新日期：1997-04-15 00:00:00
abstract：:Recently, it has been shown that the activation of the Drosophila EGF receptor (DER) by its natural ligand Spitz is inhibited by Argos [Schweitzer, R., et al. (1995) Nature 376, 699-702]. Argos and Spitz both have an EGF-like domain which in the case of Argos differs from that of Spitz and other EGF receptor agonists ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi970227f
更新日期：1997-06-17 00:00:00
