Abstract：
:Orotate phosphoribosyltranferase (OPRTase) catalyzes the formation of orotidine 5'-monophosphate from the nitrogenous base orotate and alpha-D-5-phosphoribosyl-1-pyrophosphate (PRPP). While it is known that Mg2+ is necessary for catalysis, the mechanism of activation of the phosphoribosyl transfer by Mg2+ remains unclear. The divalent cation may activate the phosphoribosyl transfer by binding to either or both substrates PRPP and orotate or/and the enzyme. In this work we chose to explore the role of divalent magnesium in activating the phosphoribosyl transfer in bacterial OPRTase. Studies on the effect of Mg2+ on the OPRTase-catalyzed reaction indicated that the divalent metal was necessary for catalysis. A maximal rate of 70 units/mg was achieved at 2 mM MgCl2. Mn2+ could replace Mg2+ as the divalent metal. Orotate methyl ester (OAME) and uracil, neither of which form chelates with divalent metal, were found to be substrates for OPRTase. The KM for OAME and uracil were 190 microM and 2.63 mM and kcat/KM were 0.91 x 10(5) and 6 M-1 s-1, respectively. These values compare with a KM of 27 microM for orotate, 44 microM for PRPP, and a kcat/KM of 1.3 x 10(6) M-1 s-1 for orotate. Spectroscopic studies failed to reveal the existence of Mg(2+)-orotate complexes. Thus we have concluded that an orotate-metal complex is not necessary for OPRTase catalysis. Metal-enzyme binding studies indicate that only weak metal-enzyme complexes may form in bacterial OPRTase. Thus the role of divalent metal in bacterial OPRTase must be to bind PRPP.
journal_name
Arch Biochem Biophysjournal_title
Archives of biochemistry and biophysicsauthors
Bhatia MB,Grubmeyer Cdoi
10.1006/abbi.1993.1290subject
Has Abstractpub_date
1993-06-01 00:00:00pages
321-5issue
2eissn
0003-9861issn
1096-0384pii
S0003-9861(83)71290-7journal_volume
303pub_type
杂志文章abstract：:Asthma is characterized by a predominant T(H)2 type immune response to airborne allergens. Controlling T(H)2 cell function has been proposed as therapy for this disease. We show here that ligands for the nuclear receptor peroxisome proliferator activated receptor (PPAR)gamma significantly reduced the immunological sym...
journal_title：Archives of biochemistry and biophysics
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journal_title：Archives of biochemistry and biophysics
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journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/0003-9861(86)90001-9
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abstract：:Catechol 1,2-dioxygenase catalyzes the oxygenative ring cleavage of catechol to form cis,cis-muconic acid and is encoded by a catA gene. We have cloned a catA gene from Pseudomonas putida mt-2 using a PCR product of amino acid sequence-based primers as a probe. The amino acid sequence deduced from the 930 nucleotides ...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.1995.1405
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pub_type： 杂志文章,评审
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pub_type： 杂志文章
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journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
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pub_type： 杂志文章
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pub_type： 杂志文章,评审
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journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/0003-9861(92)90008-k
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journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/0003-9861(92)90683-n
更新日期：1992-09-01 00:00:00
abstract：:Cellular glutathione is released during apoptosis and may play a role in the regulation of the mitochondrial permeability transition pore. The question of whether only cytosolic glutathione is important in apoptosis, or whether mitochondrial glutathione also plays a role, was investigated using gamma-glutamyltranspept...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.2001.2662
更新日期：2002-01-15 00:00:00
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journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章,评审
doi：10.1016/j.abb.2012.04.001
更新日期：2012-07-01 00:00:00
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journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章,评审
doi：10.1016/j.abb.2019.01.033
更新日期：2019-03-30 00:00:00
abstract：:Some compounds are known to induce solute-nonselective permeability of the inner mitochondrial membrane (IMM) in Ca2+-loaded mitochondria. Existing data suggest that this process, following the opening of a mitochondrial permeability transition pore, is preceded by different solute-selective permeable states of IMM. A...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.1998.0738
更新日期：1998-08-01 00:00:00
abstract：:Neutrophils and monocytes produce the highly cytotoxic hypochlorous acid (HOCl) via the myeloperoxidase (MPO)-catalyzed reaction of H2O2 with Cl-. We have investigated the reaction of reagent and MPO-derived HOCl with cholesterol in a purified liposome system, as well as progressively more complex biological systems. ...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.1996.0317
更新日期：1996-08-01 00:00:00
abstract：:Functional concerns regarding hemoglobin-based red cell substitutes have generally centered on two parameters: (a) oxygen binding and delivery properties and (b) stabilization of the hemoglobin tetramer to prevent dimerization. Strategic chemical cross-linking and site-directed mutagenesis have produced proteins that ...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.1995.1061
更新日期：1995-01-10 00:00:00
abstract：:Proteins lacking prosthetic groups and/or cofactors are known to undergo electronic excitation transitions only upon exposure to UV-C (< 280 nm) and UV-B (280-320 nm), but not UV-A (320-400 nm) photons. Here, we report the discovery of a novel excitation that peaks at approximately 340 nm and yields visible violet-blu...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
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更新日期：2004-08-15 00:00:00
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journal_title：Archives of biochemistry and biophysics
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journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/j.abb.2005.08.010
更新日期：2005-10-15 00:00:00
abstract：:Uteroglobin has been purified from hare lung by gel filtration and chromatography on carboxymethyl-cellulose. Hare uteroglobin appears homogeneous by electrophoresis under both denaturing and nondenaturing conditions. Its chemical and immunological properties as well as its ability to bind progesterone are compared to...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/0003-9861(83)90323-5
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abstract：:Vanadium salts such as vanadyl sulfate (VS), potent inhibitors of protein tyrosine phosphatases, have been shown to mimic, augment, and prolong insulin's action. However, the molecular mechanism of responses to these salts is not clear. In the present studies, we examined if VS-induced effects on insulin action are as...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/j.abb.2003.09.010
更新日期：2003-12-01 00:00:00
abstract：:Horseradish peroxidase (EC 1.11.1.7) is shown to catalyze the aerobic oxidation of lysozyme, bovine serum albumin, and protamine adducts with glycolaldehyde at physiological pH. This reaction is accompanied by light emission, which is attributed to the generation of triplet species. The intensity of chemiluminescence ...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
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abstract：:An N-acetyl-D-galactosamine-specific lectin has been isolated from the two seed forms of the hog peanut (Amphicarpaea bracteata) using an affinity support containing the synthetic type A blood group trisaccharide alpha-D-GalNAc-(1,3)-[alpha-L-Fuc-(1,2)]-beta-D-Gal (Synsorb A). The affinity-purified lectin appears to b...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/0003-9861(87)90310-9
更新日期：1987-05-15 00:00:00
abstract：:One of the key steps involved in T-cell activation is binding of the tyrosine kinase ZAP-70 via its two SH2 domains to peptide segments termed tyrosine-based activation motifs (ITAM) which are present in three of the T-cell receptor (TCR) subunits. The crystal structure of the ZAP-70 SH2 domains complexed to phosphope...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.1997.0118
更新日期：1997-06-01 00:00:00
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journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/j.abb.2006.09.011
更新日期：2006-11-15 00:00:00
abstract：:Dpo4 is a representative model of Y-family DNA polymerase and is therefore one of the most intensively studied DNA polymerase. 6 mA, an epigenetic marker, plays important roles in regulation of various biological processes. However, its effects on DNA replication by Dpo4 is completely unknown. Here, we found that 6 mA...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1016/j.abb.2019.108120
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abstract：:Stem cells maintain their self-renewal and multipotency capacities through a self-organizing network of transcription factors and intracellular pathways activated by extracellular signaling from the microenvironment or "niche" in which they reside in vivo. In the adult mammalian brain new neurons continue to be genera...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章,评审
doi：10.1016/j.abb.2012.10.001
更新日期：2013-06-01 00:00:00
abstract：:An increasing number of studies use calcium-sensitive fluorescent dyes to address the relationship between elevated levels of intracellular calcium and free-radical-mediated damage in a variety of pathophysiological phenomena. The present study evaluates the effects of reactive oxygen species on the spectral propertie...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.1997.0518
更新日期：1998-02-01 00:00:00
