scholarly journals Acidic peptides of the lens. 6. Metabolism of γ-glutamyl peptides in subcellular fractions of rabbit liver*

1961 ◽  
Vol 79 (1) ◽  
pp. 118-128 ◽  
Author(s):  
E. E. Cliffe ◽  
S. G. Waley
1993 ◽  
Vol 21 (2) ◽  
pp. 126S-126S
Author(s):  
JANE WILKINSON ◽  
JOAN A. HIGGINS ◽  
PIETER H. E. GROOT ◽  
ERMANNO GHERARDI ◽  
DAVID E. BOWYER

1992 ◽  
Vol 288 (2) ◽  
pp. 413-419 ◽  
Author(s):  
J Wilkinson ◽  
J A Higgins ◽  
P H E Groot ◽  
E Gherardi ◽  
D E Bowyer

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.


1978 ◽  
Vol 175 (2) ◽  
pp. 757-759 ◽  
Author(s):  
G Woodnutt ◽  
D S Parker

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.


1977 ◽  
Vol 55 (6) ◽  
pp. 602-608 ◽  
Author(s):  
Arun C. Dey ◽  
Ian R. Senciall

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.


1963 ◽  
Vol 10 (01) ◽  
pp. 071-080 ◽  
Author(s):  
L. B Jaques ◽  
C Mary Jaques

SummaryPreparations were made of rabbit liver globulin by the method of Jaques for heparinase and their effect on heparin studied. The results confirmed the observations of a progressive loss of anticoagulant activity with globulin in 0.9% saline, of a loss of metachromatic activity after phenol extraction and the reversal of the latter by alkali. The latter observations were due to the solubility in phenol of heparin on combination with protein. With suitable preparations, a decrease in anticoagulant activity without decrease in metachromatic activity was observed, i.e. conversion of heparin to uroheparin. Loss of heparin due to combination with protein and resulting precipitation, solubility in phenol, etc. followed a protein pH-dissociation curve. Loss of heparin anticoagulant activity due to heparinase was maximal at pH 5.4. No loss of heparin occurred at pH values more acid than 5 or more alkaline than 7.


1960 ◽  
Vol XXXIII (IV) ◽  
pp. 532-538 ◽  
Author(s):  
H. Breuer ◽  
Gerta Pangels
Keyword(s):  

ABSTRACT The metabolism of oestrone, oestradiol-17α and oestradiol-17β has been studied in rabbit liver slices. Oestradiol-17α and oestradiol-17β were isolated as metabolites of oestrone. When oestradiol-17α17α was incubated oestrone and oestradiol-17β were formed, whereas oestradiol-17β gave rise to oestradiol-17α and oestrone. Quantitative experiments showed that after incubation of oestrone 5–8 times as much oestradiol-17β was found as oestradiol-17α.


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