scholarly journals Analytical study of microsomes and isolated subcellular membranes from rat liver. VI. Electron microscope examination of microsomes for cytochrome b5 by means of a ferritin-labeled antibody.

1976 ◽  
Vol 71 (2) ◽  
pp. 551-564 ◽  
Author(s):  
J Remacle ◽  
S Fowler ◽  
H Beaufay ◽  
A Amarcostesec ◽  
J Berthet
Keyword(s):  
Electron Microscope ◽  
Rat Liver ◽  
Sucrose Gradient ◽  
Analytical Study ◽  
Cytochrome B5 ◽  
Liver Microsomes ◽  
Rat Liver Microsomes ◽  
Microscope Examination ◽  
Group B ◽  
Isopycnic Centrifugation

The distribution of cytochrome b5 in rat liver microsomes, and in two microsomal subfractions isolated by density equilibration in a linear sucrose gradient, was studied under the electron microscope by means of a ferritin-labeled hybrid anti-cytochrome b5/anti-ferritin antibody. Results of this study show that cytochrome b5 is present in essentially all microsomal vesicles derived from endoplasmic reticulum (ER), whether rough or smooth. Thus, the dissociation of ER constituents into two groups (b and c), achieved by subfractionating microsomes by isopycnic centrifugation (Beaufay, H., A. Amar-Costesec, D. Thines-Sempoux, M. Wibo, M. Robbi, and J. Berthet. 1974. J. Cell Biol. 61:213-231), does not reflect the association of each group with distinct microsomal particles but reflects rather an enzymatic heterogeneity of the ER: the ratio of group c to group b enzymes increasing with the density and ribosome load of the particles.

scholarly journals ANALYTICAL STUDY OF MICROSOMES AND ISOLATED SUBCELLULAR MEMBRANES FROM RAT LIVER

1974 ◽  
Vol 62 (3) ◽  
pp. 717-745 ◽  
Author(s):  
Alain Amar-Costesec ◽  
Maurice Wibo ◽  
Denise Thinès-Sempoux ◽  
Henri Beaufay ◽  
Jacques Berthet
Keyword(s):  
Electron Microscope ◽  
Cytochrome C ◽  
Rat Liver ◽  
Cytochrome B5 ◽  
Liver Microsomes ◽  
Equilibrium Density ◽  
Substantial Part ◽  
Rat Liver Microsomes ◽  
Cytochrome C Reductase ◽  
Nucleoside Diphosphatase

Isopycnic equilibration and sedimentation rate studies of rat liver microsomes led previously to the assignment of microsomal constituents into group a1 (monoamine oxidase), group a2 (5'-nucleotidase, alkaline phosphodiesterase I, alkaline phosphatase and cholesterol), group a3 (galactosyltransferase), group b (NADH cytochrome c reductase, NADPH cytochrome c reductase, aminopyrine demethylase, cytochrome b5 and P 450), and group c (glucose 6-phosphatase, esterase, nucleoside diphosphatase, ß-glucuronidase and glucuronyltransferase). Confirmation and extension of the assignment into groups has been obtained by studying the differential effect of the reagents digitonin, EDTA, and PPi. Digitonin specifically affected the equilibrium density only of the group a2 and (to a lesser extent) group a3, and not of groups b and c under conditions which preserved the structure-linked latency of nucleoside diphosphatase and galactosyltransferase. Within experimental error the rate of sedimentation of all microsomal constituents was unaffected. The morphological appearance under the electron microscope was indistinguishable from that of nondigitonin-treated microsomes, except that a few smooth membranes (< 10%) exhibited broken-looking profiles. Treatment of microsomes with EDTA or PPi detached a substantial part of RNA and released protein in excess over the amount accountable for by detachment of ribosome constituents. This detachment was confirmed by electron microscopy. EDTA and PPi decreased markedly the equilibrium density and the density dispersion of groups b and c, due mainly to the uncoating of rough elements. EDTA and PPi shifted slightly the distribution profiles of groups a towards lower densities, possibly as a result of the release of adsorbed proteins. The combination of EDTA and digitonin, used subsequently, rendered the average equilibrium density of group a2 higher than that of groups b and c. Dense subfractions were thus enriched in constituents of group a2 and showed mainly broken-looking vesicles under the electron microscope. The import of our results on the biochemical and enzymic properties of the subcellular components of the microsome fractions is discussed.

Inhibitory Effect of Resveratrol on the Pharmacokinetics of Ticagrelor in Vivo and Vitro

2021 ◽  
Author(s):  
Peng Wang ◽  
Xiao-Xia Hu ◽  
Ying-hui Li ◽  
Nan-Yong Gao ◽  
Guo-quan Chen ◽  
...  
Keyword(s):  
Rat Liver ◽  
Liver Microsomes ◽  
In Vitro Study ◽  
Inhibitory Effect ◽  
Control Group ◽  
Rat Liver Microsomes ◽  
Sprague Dawley ◽  
Group B

This study was to evaluate the effect of resveratrol on the pharmacokinetics of ticagrelor in rats and the metabolism of ticagrelor in human CYP3A4 and liver microsomes. Eighteen Sprague-Dawley rats were randomly divided into three groups: group A (control group), group B (50mg/kg resveratrol), and group C (150mg/kg resveratrol ). After 30 minutes administration of resveratrol, a single dose of ticagrelor (18mg/kg) was administered orally. The vitro experiment was performed to examine the influence of resveratrol on ticagrelor metabolism in CYP3A4*1, human, and rat liver microsomes. Serial biological samples were assayed by validated UHPLC-MS/MS methods. In vivo study, the AUC and Cmax of ticagrelor in group B and C appeared to be significantly higher than the control group, while Vz/F and CLz/F of ticagrelor in group B and C were significantly decreased. In vitro study, resveratrol exhibited an inhibitory effect on CYP3A4*1, human and rat liver microsomes. The IC50 values of resveratrol were 56.75μM，69.07μM and 14.22μM, respectively. Our results indicated that resveratrol had a inhibitory effect on the metabolism of ticagrelor in vitro and vivo. It should be paid more attention to the clinical combination of resveratrol with ticagrelor and ticagrelor plasma concentration should be monitored to avoid the occurrence of adverse reaction.

scholarly journals Characterization and biosynthesis of cytochrome b5 in rat liver microsomes

1968 ◽  
Vol 107 (6) ◽  
pp. 839-849 ◽  
Author(s):  
J. R. Sargent ◽  
B. P. Vadlamudi
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Spectral Properties ◽  
Proteolytic Enzymes ◽  
Cytochrome B5 ◽  
Liver Microsomes ◽  
Rat Liver Microsomes ◽  
Isolated Rat Liver ◽  
Peptide Linkage ◽  
Isolated Rat

1. Cytochrome b5 is released from rat liver microsomes by both proteolytic enzymes and by treatments that disrupt phospholipids. Cytochrome P-420 is only released to a marked extent by treatments that disrupt phospholipids. 2. Cytochrome b5 was isolated in a pure state from both the rough and smooth fractions of rat liver microsomes after treatment with trypsin, and was shown to contain two cytochrome components with identical spectral properties. 3. Amino acid analyses of the two components are presented, together with peptide ‘fingerprint’ patterns of tryptic digests of the two components. 4. Studies based on the direct isolation of cytochrome b5 after administration of a single dose of radioactive amino acid to rats demonstrate that the cytochrome is synthesized initially in the rough fraction of microsomes and only subsequently appears in the smooth fraction. 5. Isolated rat liver microsomes are capable of incorporating radioactive amino acids into cytochrome b5 under standard conditions. 6. Under these conditions the amino acid is incorporated into peptide linkage in the cytochrome.

Cytochrome b5/Cytochrome b5 Reductase Complex in Rat Liver Microsomes has NADH-Linked Aquacobalamin Reductase Activity

1992 ◽  
Vol 122 (4) ◽  
pp. 940-944 ◽  
Author(s):  
Fumio Watanabe ◽  
Yoshihisa Nakano ◽  
Hisako Saido ◽  
Yoshiyuki Tamura ◽  
Hiroyuki Yamanaka
Keyword(s):  
Rat Liver ◽  
Reductase Activity ◽  
Cytochrome B5 ◽  
Liver Microsomes ◽  
Rat Liver Microsomes ◽  
Cytochrome B5 Reductase

scholarly journals ELECTRON MICROSCOPE EXAMINATION OF SUBCELLULAR FRACTIONS

1971 ◽  
Vol 51 (1) ◽  
pp. 52-71 ◽  
Author(s):  
Maurice Wibo ◽  
Alain Amar-Costesec ◽  
Jacques Berthet ◽  
Henri Beaufay
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Membrane Protein ◽  
Distribution Pattern ◽  
Biochemical Analysis ◽  
Liver Microsomes ◽  
Rat Liver Microsomes ◽  
Microscope Examination ◽  
Membrane Area ◽  
Microsome Fraction

Rat liver microsomes and microsomal subfractions isolated by density equilibration were submitted to a quantitative morphological and biochemical analysis. The total area of the endoplasmic reticulum was estimated at 7.3 m2 per g of liver. The microsome fraction contained 2.8 mg of phospholipids and 6.7 mg of proteins per m2 of membrane area. After correction for ribosomal and intracisternal proteins, the latter value was lowered to 4.7 mg of membrane protein per m2. More than half of the microsomal vesicles carried ribosomes. After density equilibration of the microsomes, the distribution pattern of ribosomes followed closely that of RNA. The ribosome load of the microsomal vesicles increased steadily along the density gradient, indicating the existence of a continuous spectrum of microsomal entities ranging from entirely ribosome-free vesicles to vesicles heavily coated with ribosomes.

scholarly journals KINETICS OF CYTOCHROME b5 IN RAT LIVER MICROSOMES

1954 ◽  
Vol 209 (2) ◽  
pp. 945-951 ◽  
Author(s):  
Britton Chance ◽  
G.R. Williams
Keyword(s):  
Rat Liver ◽  
Cytochrome B5 ◽  
Liver Microsomes ◽  
Rat Liver Microsomes ◽  
Kinetics Of
Sign in / Sign up

Export Citation Format

Share Document