In vitro characterization of rosiglitazone metabolites and determination of the kinetic parameters employing rat liver microsomal fraction

2011 ◽  
Vol 36 (3) ◽  
pp. 159-166 ◽  
Author(s):  
Leandro Augusto Calixto ◽  
Anderson Rodrigo Moraes de Oliveira ◽  
Valquíria Aparecida Polisel Jabor ◽  
Pierina Sueli Bonato
Keyword(s):  
Kinetic Parameters ◽  
Rat Liver ◽  
Microsomal Fraction ◽  
In Vitro Characterization ◽  
Liver Microsomal Fraction

scholarly journals In Vitro Characterization of Borneol Metabolites by GC--MS Upon Incubation with Rat Liver Microsomes

2008 ◽  
Vol 46 (5) ◽  
pp. 419-423 ◽  
Author(s):  
R. Zhang ◽  
C.-h. Liu ◽  
T.-l. Huang ◽  
N.-s. Wang ◽  
S.-q. Mi
Keyword(s):  
Rat Liver ◽  
Liver Microsomes ◽  
Rat Liver Microsomes ◽  
In Vitro Characterization

scholarly journals Thyroid Hormone Action IN VITRO CHARACTERIZATION OF SOLUBILIZED NUCLEAR RECEPTORS FROM RAT LIVER AND CULTURED GH1 CELLS

1974 ◽  
Vol 54 (4) ◽  
pp. 853-865 ◽  
Author(s):  
Herbert H. Samuels ◽  
Jir S. Tsai ◽  
Juan Casanova ◽  
Frederick Stanley
Keyword(s):  
Thyroid Hormone ◽  
Nuclear Receptors ◽  
Rat Liver ◽  
Hormone Action ◽  
Thyroid Hormone Action ◽  
In Vitro Characterization

scholarly journals Kinetic properties of the Ca2+-accumulation system of a rat liver microsomal fraction

1982 ◽  
Vol 206 (1) ◽  
pp. 73-79 ◽  
Author(s):  
A P Dawson
Keyword(s):  
Rat Liver ◽  
Microsomal Fraction ◽  
Dominant Role ◽  
Kinetic Properties ◽  
Steady State Distribution ◽  
Stringent Requirement ◽  
Accumulation System ◽  
Saturation Kinetics ◽  
Liver Microsomal Fraction

1. By using Ca-EGTA buffers, the Km for Ca2+ uptake into rat liver heavy microsomes (microsomal fraction) was found to be 0.2 microM free Ca2+. 2. In the absence of oxalate, these vesicles accumulate about 20 nmol of Ca2+/mg of protein. Efflux of Ca2+ from the vesicles is much faster at pH 7.6 than at pH 6.8, but does not apparently show saturation kinetics or any stringent requirement for external ions. 3. The steady-state distribution of Ca2+ between the microsomes and the medium in the presence of ATP and the absence of oxalate is dependent on Ca2+ load. When the vesicles are loaded to 50% capacity, the external free Ca2+ concentration is 70 nM. 4. The affinity of heavy microsomes for Ca2+ is such that is seems likely that they has a dominant role in the determination of cytoplasmic free Ca2+ concentrations.

scholarly journals In vitro characterization of the yeast DcpS, a scavenger mRNA decapping enzyme

2019 ◽  
Author(s):  
Madalee G. Wulf ◽  
John Buswell ◽  
Siu-Hong Chan ◽  
Nan Dai ◽  
Katherine Marks ◽  
...  
Keyword(s):  
Reaction Conditions ◽  
Mrna Decapping ◽  
Rna Transcripts ◽  
In Vitro Characterization ◽  
Eukaryotic Mrnas ◽  
Phosphate Linkage ◽  
Decapping Enzyme

AbstractEukaryotic mRNAs are modified at their 5’ end early during transcription by the addition of N7-methylguanosine (m7G), which forms the “cap” on the first 5’ nucleotide. Identification of the 5’ nucleotide on mRNA is necessary for determination of the Transcription Start Site (TSS). We explored the effect of various reaction conditions on the activity of the yeast scavenger mRNA decapping enzyme DcpS (yDcpS) and examined decapping of 30 chemically distinct cap structures varying the state of methylation, sugar, phosphate linkage, and base composition on 25mer RNA oligonucleotides. Contrary to the generally accepted belief that DcpS enzymes only decap short oligonucleotides, we found that yDcpS efficiently decaps RNA transcripts as long as 1400 nucleotides. Further, we validated the application of yDcpS for enriching capped RNA using a strategy of specifically tagging the 5’ end of capped RNA by first decapping and then recapping it with an affinity-tagged guanosine nucleotide.

scholarly journals The effect of GTP on inositol 1,4,5-trisphosphate-stimulated Ca2+ efflux from a rat liver microsomal fraction. Is a GTP-dependent protein phosphorylation involved?

1986 ◽  
Vol 234 (2) ◽  
pp. 311-315 ◽  
Author(s):  
A P Dawson ◽  
J G Comerford ◽  
D V Fulton
Keyword(s):  
Polyethylene Glycol ◽  
Rat Liver ◽  
Microsomal Fraction ◽  
Slow Release ◽  
Protein Species ◽  
Accumulation System ◽  
Microsomal Membranes ◽  
Dependent Protein ◽  
Liver Microsomal Fraction

GTP, when added to a rat liver microsomal fraction that had previously been allowed to accumulate Ca2+, causes a slow release of Ca2+, which is greatly enhanced by addition of inositol trisphosphate (IP3). The Ca2+ release caused by IP3 under these conditions is very much greater than that observed in the absence of GTP. The effect of GTP is dependent on the presence of polyethylene glycol in the incubation medium and is not due to inhibition of the Ca2+-accumulation system. The response to GTP is time-dependent, particularly at low (4 microM) GTP concentrations, and cannot be mimicked by ATP, ITP, CTP, UTP and GDP. Studies with [gamma-32P]GTP show that, during incubation with microsomal fractions, the terminal phosphate of GTP is transferred to two protein species, of Mr 38 000 and 17 000. These protein phosphorylations are still present when an excess of unlabelled ATP is included in the incubation mixture, but appear to be unaffected by the presence or absence of IP3 and polyethylene glycol. As a working hypothesis, it is suggested that a protein, phosphorylated by GTP, has to bind to the microsomal membranes before IP3 can stimulate Ca2+ release, and that, in vitro, the binding of this protein is favoured by the presence of polyethylene glycol.

scholarly journals Metabolism of [14C]diethylstilboestrol epoxide by rat liver in vitro

1980 ◽  
Vol 185 (1) ◽  
pp. 129-137 ◽  
Author(s):  
P H Jellinck ◽  
J H Bowen
Keyword(s):  
Rat Liver ◽  
Microsomal Fraction ◽  
Water Soluble ◽  
Immature Rat ◽  
Epoxide Hydratase ◽  
New Type ◽  
Liver Microsomal Fraction ◽  
Harmful Effects

1. The trans-epoxide of diethylstilboestrol and its pinacolone were synthesized chemically and the pinacolone shown to be formed from the epoxide by a non-enzymic process. 2. [14C]Diethylstiboestrol epoxide was converted by rat liver microsomal fraction into 4'-hydroxypropiophenone by a new type of cleavage reaction involving mono-oxygenase. Conditions for the formation of this metabolite and also water-soluble products were investigated together with the effect of inhibitors. A sex-difference in the conversion of diethylstilboestrol epoxide into 4'-hydroxypropiophenone and to polar and water-soluble products was observed. 3. Diethylstilboestrol epoxide was found to be a relatively stable compound that did not form a glutathione conjugate readily without further microsomal activation. A purified preparation of epoxide hydratase did not enhance its rate of conversion into the pinacolone. 4. Diethylstilboestrol epoxide was found to have about one-tenth the oestrogenic activity of diethylstilboestrol as measured by the increase in uterine weight or the induction of peroxidase in immature rat uteri. It was inactive as a mutagen when tested for its ability to inhibit bacteriophage phi X174 DNA viral replication. 5. The possible role of diethylstilboestrol epoxide as an intermediate in the metabolism of diethylstilboestrol and in mediating the harmful effects of this synthetic estrogen is discussed.

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