Involvement of cytochrome b5 in the oxidative desaturation of linoleic acid to γ-linolenic acid in rat liver microsomes

Lipids ◽  
1977 ◽  
Vol 12 (3) ◽  
pp. 267-271 ◽  
Author(s):  
Takako Okayasu ◽  
Teruo Ono ◽  
Kazunori Shinojima ◽  
Yoh Imai
Keyword(s):  
Linoleic Acid ◽  
Linolenic Acid ◽  
Rat Liver ◽  
Cytochrome B5 ◽  
Liver Microsomes ◽  
Rat Liver Microsomes ◽  
Oxidative Desaturation

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 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 Effect of dietary fats on the δ6- and δ5-desaturation of fatty acids in rat liver microsomes

1983 ◽  
Vol 50 (3) ◽  
pp. 749-756 ◽  
Author(s):  
D. Kirstein ◽  
C.-E. Høy ◽  
G. Hølmer
Keyword(s):  
Arachidonic Acid ◽  
Linolenic Acid ◽  
Rat Liver ◽  
Desaturase Activity ◽  
Liver Microsomes ◽  
Dietary Fats ◽  
Rat Liver Microsomes ◽  
Δ5 Desaturase ◽  
Substrate Level

1. Rats were given diets containing (% dietary energy): 46 arachis oil (AO), 36 partially-hydrogenated arachis oil (HAO) + 10 AO, 36 partially-hydrogenated marine oil (HMO) + 10 AO, or 46 of a combination of rape-seed oils high and low in erucic acid (RSO + LERSO).2. In the liver microsomes the content of arachidonic acid (20:4ω6) was reduced inthe groups given HAO + AO and HMO + AO.3. The rates of Δ6-desaturation of linoleic acid into γ-linolenic acid (18:3ω6) and of Δ5-desaturation of dihomo-γ-linolenic acid into arachidonic acid were studied in vitro at two substrate levels: a high substrate level reflecting maximal microsomal desaturase activity in rat liver and a low substrate level reflecting desaturase activity under physiological conditions.4. Dietary HAO, rich in 18:1 isomers, suppressed the Δ6-desaturase activity butnot the Δ5-desaturase activity. Dietary HMO, rich in 18:1, 20:1 and 22:1 isomers, reduced both Δ6- and Δ5-desaturase activities.

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
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