bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Difference in the Carboxy-Terminal Sequence Is Responsible for the Difference in the Activity of Chicken and Rat Liver Fructose-2,6-Bisphosphatase
Authors: Zhu Zheng , Ling Song , Yang Qi-Heng , Li Lin 
Published: October 2004

AbstractThe fructose-2,6-bisphosphatase domain of the bifunctional chicken liver enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase shares approximately 95% amino acid sequence homology with that of the rat enzyme. However, these two enzymes are significantly different in their phosphatase activities. In this report, we show that the COOH-terminal 25 amino acids of the two enzymes are responsible for the different enzymatic activities. Although these 25 amino acids are not required for the phosphatase activity, their removal diminishes the differences in the activities between the two enzymes. In addition, two chimeric molecules (one consisting of the catalytic core of the chicken bisphosphatase domain and the rat COOH-terminal 25 amino acids, and the other consisting of most of the intact chicken enzyme and the rat COOH-terminal 25 amino acids) showed the same kinetic properties as the rat enzyme. Furthermore, substitution of the residues Pro456pro457Ala458of the chicken enzyme with GluAlaGlu, the corresponding sequence in the rat liver enzyme, yields a chicken enzyme that behaves like the rat enzyme. These results demonstrate that the different bisphosphatase activities of the chicken and rat liver bifunctional enzymes can be attributed to the differences in their COOH-terminal amino acid sequences, particularly the three residues.
Superoxide Reactivates Nitric Oxide-Inhibited Catalase
Authors: Kim Yu Shin , Han Sanghwa 
Published: October 2004

Abstract
Catalase binds nitric oxide (NO) to generate ferricatalase-NO, an inhibited form of the enzyme. Superoxide
(O2
−) is also an inactivator of the enzyme. We
found, however, that O2
− efficiently converted the inhibited
ferricatalase-NO to the active ferricatalase
without producing detectable intermediates. The reaction
slowed down when O2
− was disproportionated
to H2O2 and O2 by superoxide dismutase, but H2O2
could displace the heme-bound NO slowly to regenerate
ferricatalase. Reactivation was observed even
under simultaneous generation of NO and O2
− suggesting
that ferricatalase-NO reacts with O2
− fast
enough to compete with the rapid reaction of O2
− and
NO. Formation of peroxynitrite by the simultaneous
generation of NO and O2
− was only partially inhibited by
ferricatalase, presumably due to slow binding of NO to
catalase in comparison with the reaction of NO and O2
−.
Classification of Kinin Receptors
Authors: Regoli Domenico , Rizzi Anna , Perron Stephan I. , Gobeil Fernand 
Published: October 2004

AbstractThis minireview is divided into three parts: the first part refers to the characterization and classification of kinin receptors using agonists and antagonists in isolated tissues (classical pharmacology). Two kinin receptors have been considered on the basis of their distinct pharmacology, namely the B1receptor of the rabbit aorta (rank order of potency of agonists: LysdesArg9BK > desArg9BK >= LysBK>BK; apparent affinities of antagonists Lys[Leu8]desArg9BK (pIC508.4 ) > [Leu8]desArg9BK (pIC507.4)>>>HOE 140, a B2receptor antagonist, pIC50<5.0), and the B2receptor of the rabbit jugular vein (potency of agonists: LysBK = BK>>> LysdesArg9BK = desArg9BK and HOE 140 (pIC509.0)>>>Lys[Leu8]desArg9BK, pIC50<5.0). The second part describes speciesrelated B1receptor subtypes, demonstrated by different pharmacological profiles of agonists and antagonists: human, rabbit and pig subtypes (LysdesArg9BK >> desArg9B K and Lys[Leu8]desArg9BK > [Leu8]desArg9BK) and dog, rat, mouse and hamster B1receptors (desArg9BK = LysdesArg9BK and [Leu8]desArg9BK = Lys[Leu8]desArg9BK). Affinities of agonists and antagonists in some species (man, rabbit, pig) are significantly increased (at least 10-fold) by the presence of a Lys at their Nterminus. The last part describes species-related B2receptor subtypes supported by results obtained with non-peptide receptor agonists (FR 190997) and antagonists (FR 173657). While BK acts as a full agonist in man, rabbit and pig, FR 190997 behaves as a full agonist on human, as partial agonist on rabbit, and as pure antagonist on pig B2receptors. Various hypotheses are considered to interpret these findings.
Molecular Cloning and Pharmacological Characterization of the Canine B1 and B2 Bradykinin Receptors
Authors: Hess J. Fred , Hey Patricia J. , Chen Tsing-Bau , OBrien Julie , Omalley Stacey S. , Pettibone Douglas J. , Chang Raymond S. L. 
Published: October 2004

AbstractThe dog is a valuable animal model in the study of the physiological role of both the B1 and B2 bradykinin receptors. To more thoroughly characterize the pharmacological properties of the canine kinin receptors we isolated the cDNA sequence encoding the B1 and B2 bradykinin receptor subtypes and overexpressed them in Chinese hamster ovary (CHO) cells. The cDNA sequence of the canine B1 bradykinin receptor encodes a protein comprised of 350 amino acids that is 76% identical to the human B1 bradykinin receptor. The cDNA sequence of the canine B2 bradykinin receptor encodes a protein of 392 amino acids that is 81% identical to the human B2 bradykinin receptor. The amino acid sequence of the canine B1 and B2 receptors are 35% identical. Pharmacological studies of the cloned receptors revealed that the agonist affinity of the dog B1 receptor is similar to the rodent B1 receptors, and differs from the human form in that there is no preference for the presence of the Nterminal Lys residue of [desArg10]Lysbradykinin. Significantly, the B1 receptor antagonist [desArg9,Leu8]BK behaves as partial agonist on the cloned dog B1 receptor. The dog B2 receptor exhibits the classical pharmacological properties of this receptor subtype.
Structural Characterization of Fucose-Containing Oligosaccharides by High-Performance Liquid Chromatography and Matrix-Assisted Laser Desorption/ Ionization Time-of-Flight Mass Spectrometry
Authors: Suzuki Minoru , Suzuki Akemi 
Published: October 2004

AbstractEight pyridylamino (PA) derivatives of fucosecontaining oligosaccharides, which occur as free oligosaccharides in human milk and also are derived from glycosphingolipids, have been analyzed by highperformance liquid chromatography (HPLC) on normalphase and reversedphase columns, and by matrixassisted laser desorption/ionization timeofflight MALDITOF) mass spectrometry. Six out of eight PAoligosaccharides were clearly separated by both normal and reversedphase HPLC at a column temperature of 40 C, but two PAoligosaccharides, lactoNfucopentaose II [Gal?1-3(Fuc?1-4)GlcNAc?1- 3Gal?1-4GlcPA] and lactoNfucopentaose III Gal?1-4(Fuc?1-3)GlcNAc?1-3Gal?1-4GlcPA], were not separated. The two unresolved PAoligosaccharides were finally separated by reversedphase HPLC at a column temperature of 11 C. MALDITOF mass spectra of PAoligosaccharides demonstrated pseudomolecular ions as the predominant signals, therefore information about the molecular mass of each PAoligosaccharide was easily obtained. Postsource decay (PSD) MALDITOF mass spectra of PAoligosaccharides gave information about the carbohydrate sequences and carbohydrate species of each PAoligosaccharide by detecting the ions responsible for the cleavage of the glycosidic bonds. The detection limits of the PAoligosaccharides by HPLC, MALDITOF mass spectrometry, and PSD MALDITOF mass spectrometry were 20 fmol, 20 fmol, and 2 pmol, respectively. These results suggest that a system including HPLC and MALDITOF mass spectrometry or HPLC and PSD MALDITOF mass spectrometry is quite useful for the structural characterization of subpmol or pmol levels of fucosecontaining oligosaccharides, and that these methods could be used for the analysis of various types of oligosaccharides derived from glycoproteins and glycosphingolipids.
Biosynthesis of N-Acetylneuraminic Acid in Cells Lacking UDP-N-Acetylglucosamine 2-Epimerase/ N-Acetylmannosamine Kinase
Authors: Hinderlich Stephan , Berger Markus , Keppler Oliver T. , Pawlita Michael , Reutter Werner 
Published: October 2004

AbstractThe first two steps in mammalian biosynthesis of Nacetylneuraminic acid, an important carbohydrate moiety in biological recognition systems, are performed by the bifunctional enzyme UDPNacetylglucosamine 2-epimerase/Nacetylmannosamine kinase. A subclone of the human B lymphoma cell line BJAB K20, lacking UDPNacetylglucosamine 2- epimerase/Nacetylmannosamine kinase mRNA as well as epimerase activity, displayed hyposialylated, functionally impaired cell surface glycoconjugates. Here we show that this cell line surprisingly still retains Nacetylmannosamine kinase activity. A gel filtration analysis of BJAB K88 control cells, which express UDPNacetylglucosamine 2-epimerase/Nacetylmannosamine kinase, revealed two Nacetylmannosamine kinase activity peaks, one coeluting with UDPNacetylglucosamine 2-epimerase activity and one coeluting with Nacetylglucosamine kinase. For this enzyme previous studies already showed ManNAc kinase activity in vitro. In contrast, the hyposialylated BJAB K20 subclone displayed only the Nacetylmannosamine kinase peak, comigrating with Nacetylglucosamine kinase. The CMPNacetylneuraminic acid content of both K88 and K20 cells and the sialylation of cell surface glycoconjugates of K20 cells could be significantly increased by supple menting the medium with Nacetylmannosamine. This Nacetylmannosamineinduced increase was drastically reduced by cosupplementation with Nacetylglucosamine only in K20 cells. We therefore propose the phosphorylation of Nacetylmannosamine as a hitherto unrecognized role of Nacetylglucosamine kinase in living cells.
Heuristic Statistical Analysis of Fluorescence Fluctuation Data with Bright Spikes: Application to Ligand Binding to the Human Serotonin Receptor Expressed in Escherichia coli Cells
Authors: Craenenbroeck Elke Van , Vercammen Jo , Matthys Gunther , Beirlant Jan , Marot Christophe , Hoebeke Johan , Strobbe Rik , Engelborghs Yves 
Published: October 2004

AbstractA statistical method for the analysis of fluorescence fluctuation amplitudes including bright spikes is presented. This situation arises e. g. when fluorescent ligands interact with receptors carrying multiple binding sites. The technique gives information on the amount of bound ligand in solution, making it a complementary technique to fluorescence correlation spectroscopy analysis, which cannot be applied in this situation. Two simple statistical tests are proposed that can discriminate between fluorescence intensities originating from free ligands or complexes. The performance of the two tests is evaluated and compared on mixtures of a fluorophore and fluorophore coated beads that mimic the behaviour of multiliganded complexes. An application to ligand binding to the serotonin receptor, expressed on Escherichia coli cells, is also provided. Specific binding of a fluorophore to this receptor, as well as competition with several ligands, is assessed.
Determination of the Net Exchange Rate of Tubulin Dimer in Steady-State Microtubules by Fluorescence Correlation Spectroscopy
Authors: Neumann Tobias , Kirschstein Steffen O. , Gomez Juan A. Camacho , Kittler Leonhard , Unger Eberhard 
Published: October 2004

Abstract
The microtubule cytoskeleton plays an important role
in eukaryotic cells, e. g., in cell movement or morphogenesis.
Microtubules, formed by assembly of tubulin
dimers, are dynamic polymers changing randomly
between periods of growing and shortening, a property
known as dynamic instability. Another process
characterizing the dynamic behaviour is the socalled
treadmilling due to different binding constants of
tubulin at both microtubule ends.
In this study, we used tetramethylrhodamine
(TMR)labeled tubulin added to microtubule suspensions
to determine the net exchange rate (NER) of
tubulin dimers by fluorescence correlation spectroscopy
(FCS) as a measure for microtubule dynamics.
This approach, which seems to be suitable as
screening system to detect compounds influencing
the NER of tubulin dimers into microtubules at
steadystate, showed that taxol, nocodazole,
colchicine, and vinblastine affect microtubule dynamics
at concentrations as low as 10[-9] 10[-10] M.
Nucleotide-Binding Sites in the Functional Unit of Sarcoplasmic Reticulum Ca2+-ATPase as Studied by Photoaffinity Spin-Labeled 2-N3-SL-ATP
Authors: Palm Thomas , Coan Carol , Trommer Wolfgang E. 
Published: October 2004

Abstract2-N[3]SLATP [2-azido-2,3O(1-oxyl-2,2,5,5-tetramethyl 3-carbonylpyrroline) adenosine triphosphate], a photoaffinity spinlabeled derivative of ATP with a nitroxide moiety attached to the ribose ring and an azido group attached to C2 of the adenine ring, was used to study the nucleotidebinding site stoichiometry of sarcoplasmic reticulum (SR) Ca[2+]ATPase. The label was shown to bind at the catalytic site of the enzyme, even though the rate of hydrolysis was poor. A maximal binding ratio of 1 mol/mol of ATPase was found. The ESR spectra showed signals from spinspin interactions between two radicals corresponding to a distance of about 15 å between labels bound to adjacent sites on the enzyme. This indicates that the minimal functional unit of the Ca[2+]ATPase is a dimer with the nucleotidebinding sites in close proximity.
Synergistic Inhibition of the Glucocorticoid Receptor by Radicicol and Benzoquinone Ansamycins
Authors: Rosenhagen Marcus C. , Young Jason C. , Wochnik Gabriela M. , Herr Alexandra S. , Schmidt Ulrike , Hartl F. Ulrich , Holsboer Florian , Rein Theo 
Published: October 2004

Abstract
Radicicol (RAD) and the benzoquinone ansamycin
geldanamycin (GA) are potential anticancer drugs
known to inhibit heat shock protein 90 (hsp90) and,
therefore, the activation of proteins dependent on its
function such as protooncogenic kinases and nuclear
receptors. Using the glucocorticoid receptor
(GR) as a model system we analysed the effects of
RAD and various benzoquinone ansamycins. All
compounds efficiently abolished GRdependent
transactivation. Surprisingly, whenever one of the
ansamycins was applied in combination with RAD,
synergistic inhibition of GRdependent transcription
and of hormone binding of GR was observed. In contrast,
combination of two ansamycins showed no
synergy. These findings suggest synergism within
the hsp90 dimer and may open new ways to explore
hsp90 as therapeutic target.
C-Terminal Peptides of Interleukin-6 Modulate the Expression of junB Protooncogene and the Production of Fibrinogen by HepG2 Cells
Authors: Igaz Péter , Bösze Szilvia , Tóth Sára , Falus András , Hudecz Ferenc 
Published: October 2004

AbstractInterleukin-6 (IL-6) is a 185 amino acid residue helical cytokine with various biological activities (e. g. B cell development, acute phase reaction). We have investigated the role of the 168 185 Cterminal region of IL-6 in the induction of fibrinogen synthesis and expression of junB mRNA using synthetic peptides corresponding to this region. Circular dichroism spectroscopy data suggest that even truncated peptides have a strong tendency to adopt an ordered conformation. Peptides were tested alone or in combination with recombinant hIL-6 on an IL-6 responsive human hepatoma HepG2 cell line. The expression of the protooncogene junB monitored by competitive RTPCR represents an early, while the fibrinogen production detected by sandwich ELISA a late, marker of IL-6 initiated events. We found that peptides depending on their structure modulate spontaneous as well as IL-6 induced fibrinogen production and/or mRNA expression of junB by exhibiting inhibition (in the presence of IL-6) or stimulation (in the absence of IL-6).
Local Variability of the Phosphoglycerate Kinase-Triosephosphate Isomerase Fusion Protein from Thermotoga maritima MSB 8
Authors: Wassenberg Doris , Wuhrer Manfred , Beaucamp Nicola , Schurig Hartmut , Wozny Manfred , Reusch Dietmar , Fabry Stefan , Jaenicke Rainer 
Published: October 2004

AbstractThe pgktpi gene locus of Thermotoga maritima encodes both phosphoglycerate kinase (PGK) and a bienzyme complex consisting of a fusion protein of PGK with triosephosphate isomerase (TIM). No separate tpi gene for TIM is present in T. maritima. A frameshift at the end of the pgk gene has been previously proposed as a mechanism to regulate the expression of the two protein variants [Schurig et al., EMBO J. 14 (1995), 442 451]. Surprisingly, the complete T. maritima genome was found to contain a pgktpi sequence not requiring the proposed frameshift mechanism. To clarify the apparent discrepancy, a variety of DNA sequencing techniques were applied, disclosing an anomalous local variability in the pgktpi fusion region. The comparison of different DNA samples and the mass spectrometric analysis of the amino acid sequence of the natural fusion protein from T. maritima MSB8 confirmed the local variability of the DNA variants. Since not all peptide masses could be assigned, further variations are conceivable, suggesting an even higher heterogeneity of the T. maritima MSB8 strain.
Towards Specific Functions of Lysosomal Cysteine Peptidases: Phenotypes of Mice Deficient for Cathepsin B or Cathepsin L
Authors: Reinheckel T. , Deussing J. , Roth W. , Peters C. 
Published: October 2004

AbstractThe lysosomal cysteine peptidases cathepsin B and cathepsin L are abundant and ubiquitously expressed members of the papain family, and both enzymes contribute to the terminal degradation of proteins in the lysosome. However, there is accumulating evidence for specific functions of lysosomal proteases in health and disease. The generation of knock out mouse strains that are deficient in lysosomal proteases provides a valuable tool for evaluation of existing hypotheses and gaining new insights into the in vivo functions of these proteases. In this minireview, we summarise and discuss the findings obtained by analysis of mice that are devoid of cathepsin B or cathepsin L. In brief, cathepsin L appears to be critically involved in epidermal homeostasis, regulation of the hair cycle, and MHC class IImediated antigen presentation in cortical epithelial cells of the thymus. Cathepsin B plays a major role in pathological trypsinogen activation in the early course of experimental pancreatitis and contributes significantly to TNFα induced hepatocyte apoptosis.
Coenzymes Q9 and Q10, Vitamin E and Peroxidation in Rat Synaptic and Non-Synaptic Occipital Cerebral Cortex Mitochondria during Ageing
Authors: Battino Maurizio , Bompadre Stefano , Leone Luciana , Villa Roberto F. , Gorini Antonella 
Published: October 2004

AbstractGreat attention has been devoted both to ageing phenomena at the mitochondrial level and to the antioxidant status of membrane structures. These kinds of investigations are difficult to perform in the brain because of its heterogeneity. It is known that synaptic heavy mitochondria (HM) may represent an aged mitochondrial population characterized by a partial impairment of their typical mitochondrial function. We arranged a novel system requiring no extraction procedure, very limited handling of the samples and their direct injection into the HPLC apparatus, to carry out, for the first time, a systematic and concomitant determination of vitamin E, Coenzyme Q[9] (CoQ[9]) and Coenzyme Q[10] (CoQ[10]) contents in rat brain mitochondria. The trends found for CoQ[9] and CoQ[10] levels in synaptic and nonsynaptic occipital cerebral cortex mitochondria during rat ageing are consistent with previous data. Hydroperoxides (HP) differed with age and it was confirmed that in the HM fraction the summation of contributions results in an oxidatively jeopardized subpopulation. We found that vitamin E seems to increase with age, at least in nonsynaptic free (FM) and synaptic light (LM) mitochondria, while it was inclined to remain substantially constant in HM.
Membrane Activity of (Cys48Ser) Lung Surfactant Protein B Increases with Dimerisation
Authors: Zaltash Shahparak , Griffiths William J. , Beck David , Duan Chen-Xia , Weaver Timothy E. , Johansson Jan 
Published: October 2004

AbstractOne of the possible functions of lung surfactant protein B (SPB), an hydrophobic membraneassociated saposinlike protein, is to reduce the alveolar surface tension by promoting insertion of phospholipids into the air/liquid interface of the lung. SPB is a covalent homodimer; Cys48 of two polypeptides form an intermolecular disulphide bond. In order to test whether dimerisation of SPB is important for surfactant function, transgenic mice which express (Cys48Ser) human SPB in a mouse SPB null background were generated. In previous studies (Cys48Ser)SPB showed a concentrationdependent in vitro activity, suggesting that it may form noncovalent dimers. Here (Cys48Ser)SPB isolated from bronchoalveolar lavage of transgenic mice was studied at different concentrations by circular dichroism (CD) spectroscopy, pulsating bubble surfactometry, mass spectrometry and reversedphase HPLC. The results indicate that (Cys48Ser)SPB, both in a phospholipid environment and in organic solvents, is largely monomeric and exhibits low activity at concentrations lower than 1 2 M, while at higher concentrations it forms noncovalent dimers, which are nearly functionally equivalent to native SPB in vitro. Furthermore, electrospray mass spectrometry showed that more dimers were found relative to the monomer when the polarity of the solvent was decreased, and when the concentration of SPB increased. (Cys48Ser)SPB also eluted earlier than native SPB in reversedphase HPLC. Taken together, these results indicate that a polar surface is buried upon dimerisation, thereby promoting formation of interchain ion pairs between Glu51 Arg52 and Glu51Arg52.
A Selenocysteine-Containing Peroxiredoxin from the Strictly Anaerobic Organism Eubacterium acidaminophilum
Authors: Söhling Brigitte , Parther Tina , Rücknagel Karl Peter , Wagner Matthias , Andreesen Jan R. 
Published: October 2004

AbstractA strongly [75]Selabeled 22 kDa protein detected previously showed in its Nterminal sequence the highest similarity to the family of thioldependent peroxidases, now called peroxiredoxins. The respective gene prxU was cloned and analyzed. prxU encodes a protein of 203 amino acids (22470 Da) and contains an inframe UGA codon (selenocysteine) at the position of the so far strictly conserved and catalytically active Cys47. The second conserved cysteine present in 2-Cys peroxiredoxins was replaced by alanine. Heterologous expression of the Eubacterium acidaminophilum PrxU as a recombinant selenoprotein in Escherichia coli was not possible. A cysteineencoding mutant gene, prxU47C, containing UGC instead of UGA was strongly expressed. This recombinant PrxU47C mutant protein was purified to homogeneity by its affinity tag, but was not active as a thioldependent peroxidase. The identification of prxU reveals that the limited class of natural selenoproteins may in certain organisms also include isoenzymes of peroxiredoxins, previously only known as nonselenoproteins containing catalytic cysteine residues.
Characterization of C-Terminally Truncated Human Tissue Inhibitor of Metalloproteinases-4 Expressed in Pichia pastoris
Authors: Stratmann Bernd , Farr Martin , Tschesche Harald 
Published: October 2004

Abstract
The tight regulation of extracellular matrix remodeling
and degradation is of great importance in physiological
processes like development and morphogenesis,
as well as in pathological situations like tumor
invasion and metastasis. Tissue inhibitors of metalloproteinases (TIMPs) are the naturally occuring inhibitors of matrix metalloproteinases, which are involved
in matrix turnover.
In this report we describe the cloning of human
TIMP-4 from a human adenocarcinoma and an osteosarcoma cell line and the expression of the inhibitory domain in the methylotrophic yeast Pichia
pastoris. The inhibition of MMP-8, -9, -12, -13 and -14
by the Nterminal domain of TIMP-4 was analysed.
Using a fluorescent MCApeptide, K values for each
subclass of MMPs were determined. With dissociation
constants in the nanomolar range, TIMP-4 seems
to be a good inhibitor for all classes of MMPs without
remarkable preference for special MMPs.