scholarly journals Purification and photoaffinity labelling of lipid methyltransferase from rat liver

1984 ◽  
Vol 223 (1) ◽  
pp. 61-66 ◽  
Author(s):  
M A Pajares ◽  
S Alemany ◽  
I Varela ◽  
D Marin Cao ◽  
J M Mato
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Rat Liver ◽  
Short Wavelength ◽  
Protein Band ◽  
Catalytic Subunit ◽  
Photoaffinity Labelling ◽  
Methyl Donor ◽  
Single Protein Band ◽  
Single Protein

An enzyme that catalyses the three-step methylation of phosphatidylethanolamine to phosphatidylcholine as well as the methylation of fatty acids and that uses S-adenosylmethionine as the methyl donor has been purified about 200-fold from rat liver. Irradiation of the purified enzyme with a short-wavelength u.v. light in the presence of [methyl-3H]8-azido-S-adenosylmethionine followed by electrophoresis results in the incorporation of radioactivity into a single protein band of about 25 kDa. It is concluded that a single catalytic subunit catalyses the conversion of phosphatidylethanolamine into phosphatidylcholine and fatty acid methylation.

EFFECTS OF HYPOGLYCIN A ON THE METABOLISM OF AMINO ACIDS BY LIVER SLICES

1964 ◽  
Vol 42 (1) ◽  
pp. 139-142 ◽  
Author(s):  
S. J. Patrick ◽  
L. C. Stewart
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Glutamic Acid ◽  
Rat Liver ◽  
Inhibitory Effects ◽  
Liver Slices

The effects of hypoglycin A on the metabolism of L-leucine-C14, L-alanine-C14, and L-glutamic-acid-C14 by rat liver slices have been investigated. Hypoglycin exerted markedly inhibitory effects on the conversion of leucine-C14 to fatty acid, cholesterol, and CO2. Conversion of alanine-C14 and glutamic acid-C14 to fatty acids was also inhibited by hypoglycin. No effects of hypoglycin on the conversion of C14-amino acids into protein or glycogen were demonstrated.

EFFECT OF ALLOXAN, INSULIN, AND THYROXINE ON CHOLESTEROL AND FATTY ACID SYNTHESIS BY RAT LIVER HOMOGENATES

1957 ◽  
Vol 35 (1) ◽  
pp. 15-23 ◽  
Author(s):  
J. F. Scaife ◽  
B. B. Migicovsky
Keyword(s):  
Carbon Dioxide ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Rat Liver ◽  
Fatty Acid Synthesis ◽  
Sodium Acetate ◽  
Cholesterol Synthesis ◽  
Acid Synthesis ◽  
Liver Homogenates ◽  
Vitro Effect

The in vitro effect of alloxan and insulin on the synthesis of cholesterol and fatty acids from 1-C14-sodium acetate by rat liver homogenates has been examined. Alloxan caused a reduction in the incorporation of acetate into cholesterol, fatty acids, and C14O2, but an increase in the oxygen consumption and carbon dioxide production. The addition of insulin to homogenates caused a reduction in cholesterol synthesis but an increase in fatty acid synthesis both for normal and diabetic animals. Homogenates from thyrotoxic rats exhibited a marked reduction in cholesterol synthesis when compared with normal animals. C14O2 production by homogenates from starved rats was appreciably lower than for those from normal animals. With this exception no appreciable difference was found in the oxygen uptake, carbon dioxide, or C14O2 production in homogenates from normal, starved, thyroxine-treated, or diabetic animals. Synthesized cholesterol was found to be located principally in the particulate matter of the homogenates after they had been incubated with 1-C14-sodium acetate. Homogenates from starved rats showed no greater tendency to degrade preformed cholesterol during incubation than did those from normal rats.

Purification of p-hydroxyphenylpyruvate hydroxylase from rat liver—requirements for cofactors

1976 ◽  
Vol 54 (5) ◽  
pp. 423-431 ◽  
Author(s):  
Kun-Tsan Lin ◽  
John C. Crawhall
Keyword(s):  
Molecular Weight ◽  
Enzyme Activity ◽  
Rat Liver ◽  
Gel Filtration ◽  
Protein Band ◽  
Final Concentration ◽  
Assay Method ◽  
Enzyme Extract ◽  
Crude Enzyme Extract ◽  
Single Protein

Theenzyme p-hydroxyphenylpyruvate hydroxylase (EC 1.13.11.27)from rat liver was studied with the assay method which measures the release of 14CO2 from p-hydroxyphenyl [carboxyl-,14C]pyruvate. Extensive dialysis of the crude enzyme extract against Tris buffer or purification involving ammonium sulfate, gel filtration, and ion exchange results in loss of enzyme activity that can be reactivated by Fe2+, dichlorophenolindophenol, and various other agents. The effect of these activators depends critically on their final concentration in the assay media.A 70-fold purification of the enzyme fraction yielded a preparation which behaved as a single protein band in Sephadex G-150. It had an isoelectric point at 5.85 and molecular weight of 63 000. The enzyme obtained appears to be different in some respects from those described by other workers from the liver of dog, human, chicken, and frog.

Free fatty acid level in rat liver after ingestion of polyunsaturated fatty acids

Lipids ◽  
1969 ◽  
Vol 4 (1) ◽  
pp. 77-79 ◽  
Author(s):  
Akira Yamamoto ◽  
Masahiro Isozaki ◽  
Takeshi Ishibe ◽  
Mitsuo Nishikawa
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Polyunsaturated Fatty Acids ◽  
Rat Liver ◽  
Acid Level ◽  
Free Fatty Acid Level ◽  
Fatty Acid Level

EFFECT OF ALLOXAN, INSULIN, AND THYROXINE ON CHOLESTEROL AND FATTY ACID SYNTHESIS BY RAT LIVER HOMOGENATES

1957 ◽  
Vol 35 (1) ◽  
pp. 15-23 ◽  
Author(s):  
J. F. Scaife ◽  
B. B. Migicovsky
Keyword(s):  
Carbon Dioxide ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Rat Liver ◽  
Fatty Acid Synthesis ◽  
Sodium Acetate ◽  
Cholesterol Synthesis ◽  
Acid Synthesis ◽  
Liver Homogenates ◽  
Vitro Effect

The in vitro effect of alloxan and insulin on the synthesis of cholesterol and fatty acids from 1-C14-sodium acetate by rat liver homogenates has been examined. Alloxan caused a reduction in the incorporation of acetate into cholesterol, fatty acids, and C14O2, but an increase in the oxygen consumption and carbon dioxide production. The addition of insulin to homogenates caused a reduction in cholesterol synthesis but an increase in fatty acid synthesis both for normal and diabetic animals. Homogenates from thyrotoxic rats exhibited a marked reduction in cholesterol synthesis when compared with normal animals. C14O2 production by homogenates from starved rats was appreciably lower than for those from normal animals. With this exception no appreciable difference was found in the oxygen uptake, carbon dioxide, or C14O2 production in homogenates from normal, starved, thyroxine-treated, or diabetic animals. Synthesized cholesterol was found to be located principally in the particulate matter of the homogenates after they had been incubated with 1-C14-sodium acetate. Homogenates from starved rats showed no greater tendency to degrade preformed cholesterol during incubation than did those from normal rats.

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