Topography of apolipoprotein B in subcellular fractions from rabbit liver

1993 ◽  
Vol 21 (2) ◽  
pp. 126S-126S
Author(s):  
JANE WILKINSON ◽  
JOAN A. HIGGINS ◽  
PIETER H. E. GROOT ◽  
ERMANNO GHERARDI ◽  
DAVID E. BOWYER
Keyword(s):  
Apolipoprotein B ◽  
Subcellular Fractions ◽  
Rabbit Liver

scholarly journals Determination of the intracellular distribution and pool sizes of apolipoprotein B in rabbit liver

1992 ◽  
Vol 288 (2) ◽  
pp. 413-419 ◽  
Author(s):  
J Wilkinson ◽  
J A Higgins ◽  
P H E Groot ◽  
E Gherardi ◽  
D E Bowyer
Keyword(s):  
Endoplasmic Reticulum ◽  
Apolipoprotein B ◽  
Intracellular Distribution ◽  
Subcellular Fractions ◽  
Rabbit Liver ◽  
Very Low Density Lipoproteins ◽  
Apo B ◽  
Golgi Region ◽  
Membrane Bound ◽  
Vldl Assembly

We have investigated the intracellular distribution of apolipoprotein B (apo B) in rabbit liver by immunoblotting, radioimmunoassay (r.i.a.) and enzyme-linked immunoassay (e.l.i.s.a.). Apo B100 was detected in total microsomes, rough microsomes, smooth microsomes, trans-enriched Golgi and cis-enriched Golgi and membrane and cisternal-content subfractions prepared from these fractions. There was also evidence of degradation of apo B100 in the Golgi membrane fractions. The amount of apo B in the subcellular fractions detected by competitive r.i.a. or e.l.i.s.a. ranged from 1.5 micrograms/mg of protein in the rough endoplasmic reticulum to 13 micrograms/mg of protein in the trans-Golgi fraction. Using internal standards (NADPH-cytochrome c reductase for the endoplasmic reticulum and galactosyltransferase for the Golgi membranes) it was calculated that all the apo B of liver is recovered within the secretory compartment, with 63% of the total apo B in the endoplasmic reticulum and the remainder in the Golgi. When the subcellular fractions were separated into membranes and cisternal contents, 60%, 50%, 60% and 30% of the total apo B was recovered in the membrane of the rough microsomes, smooth microsomes, cis-Golgi and trans-Golgi respectively. Using competitive e.l.i.s.a. we found that the membrane-bound form of the apo B was exposed at the cytosolic surface of the intact subcellular fractions. These observations are consistent with a model for assembly of very-low-density lipoproteins (VLDL) in which newly synthesized apo B is incorporated into a membrane-bound pool and a lumenal pool. The membrane-bound pool not used for VLDL assembly may be degraded, possibly in the Golgi region.

The distribution of apolipoprotein B in endoplasmic reticulum and Golgi subfractions of rabbit liver

1990 ◽  
Vol 18 (6) ◽  
pp. 1181-1181 ◽  
Author(s):  
JANE WILKINSON ◽  
JOAN A. HIGGINS ◽  
PIETER H. E. GROOT ◽  
ERMANNO GHERARDI ◽  
DAVID E. BOWYER
Keyword(s):  
Endoplasmic Reticulum ◽  
Apolipoprotein B ◽  
Rabbit Liver

scholarly journals Rabbit liver acetyl-CoA synthetase

1978 ◽  
Vol 175 (2) ◽  
pp. 757-759 ◽  
Author(s):  
G Woodnutt ◽  
D S Parker
Keyword(s):  
Subcellular Fractions ◽  
Rabbit Liver ◽  
Acetyl Coa ◽  
Assay Medium ◽  
Liver Homogenates

Acetyl-CoA synthetase (EC 6.2.1.1) was assayed in subcellular fractions of rabbit liver homogenates. The activity was located almost exclusively in the cytosol. There was no decrease in activity when butyrate or propionate (each at 5–20 mM) were added to the assay medium.

C-21- and 6-hydroxylation of progesterone by rabbit liver subcellular fractions

1977 ◽  
Vol 55 (6) ◽  
pp. 602-608 ◽  
Author(s):  
Arun C. Dey ◽  
Ian R. Senciall
Keyword(s):  
Microsomal Fraction ◽  
Liver Microsomes ◽  
Subcellular Fractions ◽  
Rabbit Liver ◽  
Microsomal Metabolism ◽  
Maximal Yield ◽  
First Time ◽  
Hydroxy Metabolites

In vitro C-21-hydroxylation of [3H]progesterone (P) has been demonstrated for the first time with rabbit liver microsomes and mitochondria. Deoxycorticosterone (DOC) was rigorously characterized as a metabolite of both mitochondrial and microsomal metabolism, whereas 6α-hydroxy DOC and 6α-hydroxy P were only identified as microsomal metabolites. 6β-Hydroxy metabolites were also detected but were of less quantitative significance. Formation of 6α-hydroxy P and 6α-hydroxy DOC increased steadily between 5 and 120 min of incubation with the microsomal fraction, whereas DOC increased up to 30 min of incubation and then declined. Maximal yield of DOC was 25.9 and 22.5 pmol/mg protein with the mitochondrial and microsomal fractions, respectively.

Sign in / Sign up

Export Citation Format

Share Document