scholarly journals Cloning of rat brain succinyl-CoA:3-oxoacid CoA-transferase cDNA. Regulation of the mRNA in different rat tissues and during brain development

1987 ◽  
Vol 248 (3) ◽  
pp. 853-857 ◽  
Author(s):  
M K Ganapathi ◽  
M Kwon ◽  
P M Haney ◽  
C McTiernan ◽  
A A Javed ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Rat Brain ◽  
Ketone Bodies ◽  
Rat Kidney ◽  
Relative Rate ◽  
Cdna Clones ◽  
Rat Tissues ◽  
Transferase Activity ◽  
Coa Transferase ◽  
Old Rats

3-Oxoacid CoA-transferase, which catalyses the first committed step in the oxidation of ketone bodies, is uniquely regulated in developing rat brain. Changes in 3-oxoacid CoA-transferase activity in rat brain during the postnatal period are due to changes in the relative rate of synthesis of the enzyme. To study the regulation of this enzyme, we identified, with a specific polyclonal rabbit anti-(rat 3-oxoacid CoA-transferase), two positive cDNA clones (approx. 800 bp) in a lambda gtll expression library, constructed from poly(A)+ RNA from brains of 12-day-old rats. One of these clones (lambda CoA3) was subcloned into M13mp18 and subjected to further characterization. Labelled single-stranded probes prepared by primer extension of the M13mp18 recombinant hybridized to a 3.6 kb mRNA. Rat brain mRNA enriched by polysome immunoadsorption for a single protein of size 60 kDa which corresponds to the precursor form of 3-oxoacid CoA-transferase was also found to be similarly enriched for the hybridizable 3.6 kb mRNA complementary to lambda CoA3. Affinity-selected antibody to the lambda CoA3 fusion protein inhibited 3-oxoacid CoA-transferase activity present in rat brain mitochondrial extracts. The 3.6 kb mRNA for 3-oxoacid CoA-transferase was present in relative abundance in rat kidney and heart, to a lesser extent in suckling brain and mammary gland and negligible in the liver. The specific mRNA was also found to be 3-fold more abundant in the brain from 12-day-old rats as compared with 18-day-old foetuses and adult rats, corresponding to the enzyme activity and relative rate of synthesis profile during development. These data suggest that 3-oxoacid CoA-transferase enzyme activity is regulated at a pretranslational level.

scholarly journals Comparative studies on 3-oxo acid coenzyme A transferase from various rat tissues

1974 ◽  
Vol 142 (3) ◽  
pp. 619-627 ◽  
Author(s):  
Allan Fenselau ◽  
Kathleen Wallis
Keyword(s):  
Citrate Synthase ◽  
Ketone Bodies ◽  
Rat Kidney ◽  
Gel Filtration ◽  
Close Correlation ◽  
Rat Tissues ◽  
Transferase Activity ◽  
Marker Enzyme ◽  
Coa Transferase ◽  
Mitochondrial Fractions

1. Tissue activities, intracellular distribution as well as selected kinetic and molecular properties of succinyl-CoA–3-oxo acid CoA transferase (EC 2.8.3.5), which is an initiator of ketone body usage, were examined in rat kidney, heart, brain, skeletal muscle and liver. 2. The activities of the transferase in these tissues are similar to reported values and are somewhat affected by the homogenization medium. Higher recoveries of activity are obtained when a phosphate buffer is used during the homogenization; Tris solutions containing sucrose and mannitol lead to only slightly lower recoveries, but can be used in studies to determine the subcellular localization of the transferase activity. 3. A close correlation was observed between the relative activities of citrate synthase (a mitochondrial marker enzyme) and CoA transferase in the cytoplasmic, particulate and mitochondrial fractions from the five tissues. 4. The Km values for acetoacetate (measured in two different ways), the ratio of Vmax. values for the two enzyme-catalysed half-reactions, and succinate product inhibition are quite similar for the enzyme from each tissue. 5. The enzymes are also similar in molecular weight (with an approx. mol.wt. of 100000 as determined by gel filtration). All show an active band in isoelectric-focusing studies with pI 7.6, except for the enzyme from heart (pI 6.8). 6. The results demonstrate a mitochondrial origin for CoA transferase in these rat tissues and support the proposition that CoA transferase is a ketolytic enzyme, i.e. an enzyme uniquely involved in the complete oxidation of ketone bodies. The structural and functional similarities of these transferases suggest that factors other than differences in Km values account for differences in the utilization of ketone bodies by various tissues.

scholarly journals Activities of enzymes of ketone-body utilization in brain and other tissues of suckling rats

1971 ◽  
Vol 121 (1) ◽  
pp. 49-53 ◽  
Author(s):  
M. Ann Page ◽  
H. A. Krebs ◽  
D. H. Williamson
Keyword(s):  
Rat Brain ◽  
Ketone Body ◽  
Ketone Bodies ◽  
Rat Kidney ◽  
Adult Brain ◽  
Suckling Period ◽  
Suckling Rats ◽  
Adult Rat ◽  
Coa Transferase ◽  
High Concentrations

1. The activities of 3-hydroxybutyrate dehydrogenase and 3-oxo acid CoA-transferase in rat brain at birth were found to be about two-thirds of those of adult rat brain, expressed per g wet wt. The activities rose throughout the suckling period and at the time of weaning reached values about three times higher than those for adult brain. Later they gradually declined. 2. At birth the activity of acetoacetyl-CoA thiolase in rat brain was about 60% higher than in the adult. During the suckling period there was no significant change in activity. 3. In rat kidney the activities of the three enzymes at birth were less than one-third of those at maturity. They gradually rose and after 5 weeks approached the adult value. Similar results were obtained with rat heart. 4. The activity of glutamate dehydrogenase (a mitochondrial enzyme like 3-hydroxybutyrate dehydrogenase and 3-oxo acid CoA-transferase) also rose in brain and kidney during the suckling period, but at no stage did it exceed the adult value. 5. Throughout the suckling period the total ketone-body concentration in the blood was about six times higher than in adult fed rats, and the concentration of free fatty acids in the blood was three to four times higher. 6. It is concluded that the rate of ketone-body utilization in brains of suckling rats is determined by both the greater amounts of the key enzymes in the tissue and the high concentrations of ketone bodies in the blood. In addition, the low activities of the relevant enzymes in kidney and heart of suckling rats may make available more ketone bodies for the brain.

scholarly journals Effect of hyperphenylalaninaemia on lipid synthesis from ketone bodies by rat brain

1976 ◽  
Vol 154 (2) ◽  
pp. 319-325 ◽  
Author(s):  
M S. Patel ◽  
O E. Owen
Keyword(s):  
Rat Brain ◽  
Ketone Bodies ◽  
Brain Slices ◽  
Lipid Synthesis ◽  
Coa Transferase ◽  
Old Rats ◽  
And Function ◽  
Developing Rat

The effect of hyperphenylalaninaemia on the metabolism of ketone bodies in vivo and in vitro by developing rat brain was investigated. The incorporation in vivo of [14C]acetoacetate into cerebral lipids was decreased by both chronic (for 3 days) and acute (for 6h) hyperphenylalaninaemia induced by injecting phenylalanine into 1-week-old rats. In studies in vitro it was observed that the incorporation of the radioactivity from [14C]acetoacetate and 3-hydroxy[14C]butyrate into cerebral lipids was inhibited by phenyl-pyruvate, but not by phenylalanine. Phenylpyruvate also inhibited the incorporation of 3H from 3H2O into lipids by brain slices metabolizing either 3-hydroxybutyrate or acetoacetate in the presence of glucose. These findings suggest that the decrease in the incorporation in vivo of [14C]acetoacetate into cerebral lipids in hyperphenylalaninaemic rats is most likely caused by phenylpyruvate and not by phenylalanine. Phenylpyruvate as well as phenylalanine had no inhibitory effects on ketone-body-catabolizing enzymes, namely 3-hydroxybutyrate dehydrogenase, 3-oxo acid CoA-transferase and acetoacetyl-CoA thiolase, in rat brain. Phenylpyruvate but not phenylalanine inhibited the activity of the 2-oxoglutarate dehydrogenase complex from rat and human brain. These findings suggest that the metabolism of ketone bodies is impaired in brains of untreated phenylketonuric patients, and in turn may contribute to the diminution of mental development and function associated with phenylketonuria.

scholarly journals Effect of phenylalanine metabolites on the activities of enzymes of ketone-body utilization in brain of suckling rats

1976 ◽  
Vol 160 (2) ◽  
pp. 217-222 ◽  
Author(s):  
J Benavides ◽  
C Gimenez ◽  
F Valdivieso ◽  
F Mayor
Keyword(s):  
Enzyme Activity ◽  
Mental Retardation ◽  
Rat Brain ◽  
Ketone Body ◽  
Lipid Synthesis ◽  
Developing Brain ◽  
Transferase Activity ◽  
Suckling Rats ◽  
Coa Transferase ◽  
The Brain

1. The effects of phenylalanine and its metabolites (phenylacetate, phenethylamine, phenyl-lactate, o-hydroxyphenylacetate and phenylpyruvate) on the activity of 3-hydroxybutyrate dehydrogenase (EC 1.1.1.30) 3-oxo acid CoA-transferase (EC 2.8.3.5) and acetoacetyl-CoA thiolase (EC 2.3.1.9) in brain of suckling rats were investigated. 2. The 3-hydroxybutyrate dehydrogenase from the brain of suckling rats had a Km for 3-hydroxybutyrate of 1.2 mM. Phenylpyruvate, phenylacetate and o-hydroxyphenylacetate inhibited the enzyme activity with Ki values of 0.5, 1.3 and 4.7 mM respectively. 3. The suckling-rat brain 3-oxo acid CoA-transferase activity had a Km for acetoacetate of 0.665 mM and for succinyl (3-carboxypropionyl)-CoA of 0.038 mM. The enzyme was inhibited with respect to acetoacetate by phenylpyruvate (Ki equals 1.3 mM) and o-hydroxyphenylacetate (Ki equals 4.5 mM). The reaction in the direction of acetoacetate was also inhibited by phenylpyruvate (Ki equals 1.6 mM) and o-hydroxyphenylacetate (Ki equals 4.5 mM). 4. Phenylpyruvate inhibited with respect to acetoacetyl-CoA both the mitochondrial (Ki equals 3.2 mM) and cytoplasmic (Ki equals 5.2 mM) acetoacetyl-CoA thiolase activities. 5. The results suggest that inhibition of 3-hydroxybutyrate dehydrogenase and 3-oxo acid CoA-transferase activities may impair ketone-body utilization and hence lipid synthesis in the developing brain. This suggestion is discussed with reference to the pathogenesis of mental retardation in phenylketonuria.

Effect of Thyroid Hormones on the 3-Oxo Acid CoA-Transferase Activity in Rat Brain during Development

Enzyme ◽  
1980 ◽  
Vol 25 (2) ◽  
pp. 106-110 ◽  
Author(s):  
J. Diez-Guerra ◽  
M.C. Aragón ◽  
C. Giménez ◽  
F. Valdivieso
Keyword(s):  
Thyroid Hormones ◽  
Rat Brain ◽  
Transferase Activity ◽  
Coa Transferase

scholarly journals Activities of enzymes involved in acetoacetate utilization in adult mammalian tissues

1971 ◽  
Vol 121 (1) ◽  
pp. 41-47 ◽  
Author(s):  
D. H. Williamson ◽  
Margaret W. Bates ◽  
M. Ann Page ◽  
H. A. Krebs
Keyword(s):  
Ketone Body ◽  
Alloxan Diabetes ◽  
Adrenal Glands ◽  
Ketone Bodies ◽  
Rat Tissues ◽  
Adult Rat ◽  
Coa Transferase ◽  
Mammalian Tissues ◽  
Fat Feeding ◽  
Low Activity

1. The activities in rat tissues of 3-oxo acid CoA-transferase (the first enzyme involved in acetoacetate utilization) were found to be highest in kidney and heart. In submaxillary and adrenal glands the activities were about one-quarter of those in kidney and heart. In brain it was about one-tenth and was less in lung, spleen, skeletal muscle and epididymal fat. No activity was detectable in liver. 2. The activities of acetoacetyl-CoA thiolase were found roughly to parallel those of the transferase except for liver and adrenal glands. The high activity in the latter two tissues may be explained by additional roles of thiolase, namely, the production of acetyl-CoA from fatty acids. 3. The activities of the two enzymes in tissues of mouse, gerbil, golden hamster, guinea pig and sheep were similar to those of rat tissues. The notable exception was the low activity of the transferase and thiolase in sheep heart and brain. 4. The activities of the transferase in rat tissues did not change appreciably in starvation, alloxan-diabetes or on fat-feeding, where the rates of ketone-body utilization are increased. Thiolase activity increased in kidney and heart on fat-feeding. 5. The activity of 3-hydroxybutyrate dehydrogenase did not change in rat brain during starvation. 6. The factors controlling the rate of ketone-body utilization are discussed. It is concluded that the activities of the relevant enzymes in the adult rat do not control the variations in the rate of ketone-body utilization that occur in starvation or alloxan-diabetes. The controlling factor in these situations is the concentration of the ketone bodies in plasma and tissues.

Physical training reverses defect in 3-ketoacid CoA-transferase activity in skeletal muscle of diabetic rats

2005 ◽  
Vol 288 (4) ◽  
pp. E748-E752 ◽  
Author(s):  
Adil El Midaoui ◽  
Jean Louis Chiasson ◽  
Gilles Tancrède ◽  
André Nadeau
Keyword(s):  
Skeletal Muscle ◽  
Plasma Concentration ◽  
Physical Training ◽  
Ketone Bodies ◽  
Diabetic Rats ◽  
Transferase Activity ◽  
Hydroxybutyric Acid ◽  
Beneficial Effects ◽  
Coa Transferase ◽  
Key Enzyme

To investigate one potential mechanism whereby physical training improves the plasma concentration of ketone bodies in experimental diabetes mellitus, we measured the activity of 3-ketoacid CoA-transferase, the key enzyme in the peripheral utilization of ketone bodies. Diabetes was induced with streptozotocin (50 mg/kg) and training carried out on a treadmill with a progressive 10-wk program. Diabetes resulted in an increase ( P < 0.001) in plasma concentration of β-hydroxybutyric acid in sedentary rats, which was partly reversed by training ( P < 0.001). Diabetes was also associated with a decreased activity of 3-ketoacid CoA-transferase in gastrocnemius muscle. When expressed per total gastrocnemius, training increased the activity of 3-ketoacid CoA-transferase by 66% in nondiabetic rats ( P < 0.001) and by 150% in diabetic rats ( P < 0.001), the decrease present in diabetic rats being fully reversed by training. Simple linear regression between the log of 3-ketoacid CoA-transferase activity and the log of plasma β-hydroxybutyric acid levels showed a statistically significant ( r = 0.563, P < 0.001) negative correlation. The beneficial effects of training on plasma ketone bodies in diabetic rats are probably explained, at least in part, by an increase in ketone body utilization, mediated by an increase in skeletal muscle 3-ketoacid CoA-transferase activity.

scholarly journals A high-MUFA diet alone does not affect ketone body metabolism, but reduces glycated hemoglobin when combined with exercise training in diabetic rats

2017 ◽  
Vol 9 (1) ◽  
pp. 31-40
Author(s):  
Juraiporn Somboonwong ◽  
Khunkhong Huchaiyaphum ◽  
Onanong Kulaputana ◽  
Phisit Prapunwattana
Keyword(s):  
Exercise Training ◽  
Ketone Body ◽  
Glycated Hemoglobin ◽  
Ketone Bodies ◽  
Transferase Activity ◽  
Nonesterified Fatty Acids ◽  
Regular Diet ◽  
Coa Transferase ◽  
Ketone Body Metabolism ◽  
Mufa Diet

Abstract Background Monounsaturated fat (MUFA) also has glucose-lowering action, but its effect on ketone bodies is unknown. Objectives To examine the effects of high-MUFA diet alone or in combination with exercise training, which can improve glucose and ketone body metabolism, in a rat model of diabetes. Methods Wistar rats were administered streptozotocin to induce diabetes and then randomly divided into five groups: sedentary rats fed a regular diet (1), a high-saturated-fat diet (2), a high-MUFA diet (3); and exercisetrained rats fed a regular diet (4), and a high-MUFA diet (5). Training was by a treadmill twice daily, 5 days/week. At 12 weeks, glucose, glycated hemoglobin (HbA1c), insulin, nonesterified fatty acids (NEFA), and β-hydroxybutyrate levels were measured in cardiac blood. Activity of the overall ketone synthesis pathway was determined in liver and 3-ketoacyl-CoA transferase activity determined in gastrocnemius muscle. Results A high-MUFA diet tended to lower plasma glucose without affecting other biochemical variables. Training did not change glucose metabolism, but significantly reduced serum NEFA. Only the high-MUFA diet plus training significantly decreased HbA1c levels. Hepatic ketone synthesis was decreased and 3-ketoacyl-CoA transferase activity was increased by training alone or in combination with a high-MUFA diet. Changes in NEFA, β-hydroxybutyrate, and the enzymatic activities in response to training plus a high-MUFA diet were comparable to those caused by training alone. Conclusion A high-MUFA diet alone does not alter ketone body metabolism. Combination of a MUFA-rich diet and exercise training is more effective than either MUFA or exercise alone for lowering HbA1c.

scholarly journals Lipogenesis from ketone bodies in rat brain. Evidence for conversion of acetoacetate into acetyl-coenzyme A in the cytosol

1976 ◽  
Vol 156 (3) ◽  
pp. 603-607 ◽  
Author(s):  
M S Patel ◽  
O E Owen
Keyword(s):  
Rat Brain ◽  
Ketone Bodies ◽  
Brain Mitochondria ◽  
Atp Citrate Lyase ◽  
Acetyl Coa ◽  
Cellular Compartment ◽  
Brain Lipids ◽  
Acetyl Coenzyme A ◽  
Citrate Lyase ◽  
Old Rats

The metabolism of acetoacetate via a proposed cytosolic pathway in brain of 1-week-old rats was investigated. (-)-Hydroxycitrate, an inhibitor of ATP citrate lyase, markedly inhibited the incorporation of carbon from labelled glucose and 3-hydroxybutyrate into cerebral lipids, but had no effect on the incorporation of labelled acetate and acetoacetate into brain lipids. Similarly, n-butylmalonate and benzene-1,2,3-tricarboxylate inhibited the incorporation of labelled 3-hydroxybutyrate but not of acetoacetate into cerebral lipids. These inhibitors had no effect on the oxidation to 14CO2 of the labelled substrates used. (-)-Hydroxycitrate decreased the incorporation of 3H from 3H2O into cerebral lipids by slices metabolizing either glucose or 3-hydroxybutyrate, but not in the presence of acetoacetate. (-)-Hydroxycitrate also differentially inhibited the incorporation of [2-14C]-leucine and [U-14C]leucine into cerebral lipids. The data show that, although the acetyl moiety of acetyl-CoA generated in brain mitochondria is largely translocated as citrate from these organelles to the cytosol, a cytosolic pathway exists by which acetoacetate is converted directly into acetyl-COA in this cellular compartment.

Soluble endothelin degradation enzyme activities in various rat tissues

1992 ◽  
Vol 70 (12) ◽  
pp. 1385-1389 ◽  
Author(s):  
Yilun Deng ◽  
Arco Y. Jeng
Keyword(s):  
Enzyme Activity ◽  
Protease Inhibitors ◽  
Rat Kidney ◽  
Cathepsin L ◽  
Biochemical Properties ◽  
Rat Tissues ◽  
Thiol Protease ◽  
Endothelin 1 ◽  
Cathepsin H ◽  
Thiol Proteases

From soluble extract of rat kidney we have previously identified an endothelin degradation enzyme that rapidly and specifically cleaves off the C-terminal tryptophan of endothelin-1, resulting in a peptide that is three orders of magnitude weaker in potency than endothelin-1 in causing smooh muscle contraction. The tissue distribution of this enzyme was examined, and the soluble extracts of rat kidney were found to contain the highest enzyme activity, followed by the spleen and the liver. In contrast, no enzyme activity was detected in the soluble extracts of brain, heart, and lung. The biochemical properties of the partially purified enzyme from kidney were further investigated. The optimal pH of the enzyme was between 5 and 7. The endothelin degrading activity was effectively blocked by thiol protease inhibitors such as benzyloxycarbonyl-Phe-Ala-diazomethyl ketone and p-hydroxymereuribenzoic acid, as well as by phenylmethylsulfonyl fluoride, but not by metalloprotease and other serine protease inhibitors. This enzyme displayed a clear difference in substrate specificity when compared with other thiol proteases such as cathepsin B, cathepsin H, and cathepsin L, known to be present in the kidney. These results suggest that a novel protease with endothelin degrading activity is widely distributed in a number of tissues.Key words: endothelin, endothelin degradation enzyme, thiol protease, carboxypeptidase.

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