scholarly journals Activation and inactivation of phosphoenolpyruvate carboxykinase by ferrous ions

1980 ◽  
Vol 185 (2) ◽  
pp. 451-454 ◽  
Author(s):  
C H Reynolds
Keyword(s):  
Rat Liver ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Protein Fractions ◽  
Time Dependent ◽  
Ferrous Ions ◽  
Irreversible Loss ◽  
Liver Cytosol ◽  
Rat Liver Cytosol

Phosphoenolpyruvate carboxykinase from rat liver cytosol is activated by Fe2+ ions in either direction of catalysis. Preincubation of the purified enzyme with Fe2+ ions causes a time-dependent irreversible loss of activity; this is not seen with unpurified enzyme. Purified enzyme can be protected from inactivation by Fe2+ ions by partially purified protein fractions from liver (ferroactivator fractions). The possible role of ferroactivator and Fe2+ ions in regulating phosphoenolpyruvate carboxykinase is discussed.

scholarly journals Alterations in translatable messenger RNA coding for phosphoenolpyruvate carboxykinase (GTP) in rat liver cytosol during deinduction.

1978 ◽  
Vol 253 (12) ◽  
pp. 4327-4332
Author(s):  
D. Kioussis ◽  
L. Reshef ◽  
H. Cohen ◽  
S.M. Tilghman ◽  
P.B. Iynedjian ◽  
...  
Keyword(s):  
Rat Liver ◽  
Messenger Rna ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Liver Cytosol ◽  
Rat Liver Cytosol

scholarly journals Epoxyeicosatrienoic acid stimulates ADP-ribosylation of a 52 kDa protein in rat liver cytosol

1992 ◽  
Vol 281 (1) ◽  
pp. 185-190 ◽  
Author(s):  
K Seki ◽  
A Hirai ◽  
M Noda ◽  
Y Tamura ◽  
I Kato ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Rat Liver ◽  
Epoxyeicosatrienoic Acid ◽  
Liver Cytosol ◽  
Adp Ribosylation ◽  
A Subunit ◽  
Gs Alpha ◽  
Adp Ribosyltransferase ◽  
Rat Liver Cytosol

In rat liver cytosol, rapid ADP-ribosylation of a 52 kDa protein by endogenous ADP-ribosyltransferase(s) was observed. This ADP-ribosylation was stimulated dose-dependently by 14,15-epoxyeicosatrienoic acid (14,15-EET), one of the metabolites of arachidonic acid by NADPH-dependent cytochrome P-450 mono-oxygenase. This stimulatory effect required the presence of GTP or its non-hydrolysable analogues, guanosine 5′-[beta gamma-imido]triphosphate or guanosine 5′-[gamma-thio]triphosphate. Of four regioisomeric EETs, 14,15-EET was the most potent. No stimulatory effect was observed with addition of 14,15-dihydroxyeicosatrienoic acid, a stable metabolite of 14,15-EET. The 52 kDa protein was not ADP-ribosylated by cholera toxin A subunit and pertussis toxin, and was not recognized by anti-Gs alpha and anti-Gi alpha antibodies. However, the 52 kDa protein could be photoaffinity-labelled with 8-azidoguanosine 5′-[alpha-32P]triphosphate. These results suggest that the 52 kDa protein is neither Gs nor Gi, though it may have a GTP-binding site. These results contribute to the understanding of the role of mono-oxygenase metabolites of arachidonic acid in intracellular signal transduction.

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