scholarly journals Isoenzymes of phosphofructokinase in the rat. Demonstration of the three non-identical subunits by biochemical, immunochemical and kinetic studies

1985 ◽  
Vol 229 (2) ◽  
pp. 333-341 ◽  
Author(s):  
S Vora ◽  
R Oskam ◽  
G E Staal
Keyword(s):  
Skeletal Muscle ◽  
Rat Brain ◽  
Genetic Control ◽  
Kinetic Studies ◽  
Rat Brain And Liver ◽  
P Type ◽  
Regulatory Properties ◽  
The Brain ◽  
Citrate Inhibition ◽  
Allosteric Properties

In man and the rabbit, 6-phosphofructokinase (PFK, EC 2.7.1.11) exists in tetrameric isoenzymic forms composed of muscle (M or A), liver (L or B) and platelet or brain (P or C) subunits, which are under separate genetic control. In contrast, the genetic control of the rat PFK has not yet been conclusively established; it is unclear whether the P-type or C-type subunit exists in this species. To resolve this question, we investigated the enzyme from the skeletal muscle, liver and brain of rats of Wag/Rij strain. Our studies demonstrate that the rat PFK is also under the control of three structural loci and that the homotetramers M4, P4 and L4 exhibit unique chromatographic, immunological and kinetic-regulatory properties. Skeletal-muscle and brain PFKs consist of isolated M4 and P4 homotetramers respectively. Although liver PFK consists predominantly of L4 homotetramer, it also contains small amounts of PL3 and P2L2 species. All three PFKs exhibit allosteric properties: co-operativity with fructose 6-phosphate and inhibition by ATP decrease in the order P4 greater than L4 greater than M4. P4 and M4 tetramers are the most sensitive to citrate inhibition, whereas L4 tetramer is the least sensitive. More importantly, P4 and L4 isoenzymes are the most sensitive to activation by fructose 2,6-bisphosphate, whereas M4 isoenzyme is the least sensitive. These results indicate that the brain PFK in this strain of rat is a unique tetramer, P4, which also exhibits allosteric kinetics, as do the well-studied M4 and L4 isoenzymes. The reported differences in the number and nature of isoenzymes present in the rat brain and liver most probably reflect the differences in the strains studied by previous investigators. Since the nature of the rat PFK isoenzymes and nomenclatures reported by previous investigators have been now reconciled, it is proposed that, for the sake of uniformity, only well-established nomenclatures used for the rabbit or human PFK isoenzymes be used for the rat isoenzymes.

Subcellular Distribution of DNA Polymerase Activity in Newborn Rat Brain and Liver

1971 ◽  
Vol 49 (12) ◽  
pp. 1285-1291 ◽  
Author(s):  
M. R. V. Murthy ◽  
A. D. Bharucha
Keyword(s):  
Enzyme Activity ◽  
Rat Brain ◽  
Dna Polymerase ◽  
Subcellular Fraction ◽  
Polymerase Activity ◽  
Particulate Material ◽  
Newborn Rat ◽  
Newborn Brain ◽  
Rat Brain And Liver ◽  
The Brain

DNA polymerase activities were determined in the cytoplasmic soluble, the nuclear soluble, and the nuclear particulate fractions of newborn rat brain and liver. The results indicate that a majority of the brain nuclear enzyme may be bound to particulate material while a majority of the liver nuclear enzyme may be free or only loosely bound. Although the subcellular distributions of DNA polymerase activity are widely different in newborn brain and liver, the enzyme activity in any given subcellular fraction is higher in liver than in brain.

scholarly journals Developmental regulation of calmodulin gene expression in rat brain and skeletal muscle.

1991 ◽  
Vol 2 (10) ◽  
pp. 819-826 ◽  
Author(s):  
J Weinman ◽  
B Della Gaspera ◽  
A Dautigny ◽  
D Pham Dinh ◽  
J Wang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Rat Brain ◽  
Blot Analysis ◽  
Temporal Pattern ◽  
Developmental Regulation ◽  
Mrna Levels ◽  
Calmodulin Gene ◽  
The Brain ◽  
Rna Blot Analysis

Three different calmodulin genes that encode the identical protein have been identified in the rat (Nojima, 1989); however, calmodulin gene expression at the various stages of tissue differentiation and maturation has not been previously determined. We have quantitated the content of mRNAs encoding calmodulin in the developing brain and skeletal muscle using RNA blot analysis with three specific cDNA probes. Our results show that five species of calmodulin mRNAs: 4.0 and 1.7 kb for CaM I, 1.4 kb for CaM II, and 2.3 and 0.8 kb for CaM III are detectable at all ages in the brain as well as in skeletal muscle but exhibit a tissue-specific developmental pattern of expression. The comparison of the temporal pattern of calmodulin gene expression with both mitotic activity, as demonstrated by cyclin A mRNA levels, and differentiation and maturation of specific brain or muscle regions is consistent with calmodulin involvement in development.

scholarly journals Response of the brain to enrichment

2001 ◽  
Vol 73 (2) ◽  
pp. 211-220 ◽  
Author(s):  
MARIAN C. DIAMOND
Keyword(s):  
Cerebral Cortex ◽  
Rat Brain ◽  
Genetic Control ◽  
Cognitive Processing ◽  
Brain Structure ◽  
Environmental Enrichment ◽  
Structural Components ◽  
Policy Makers ◽  
Environmental Input ◽  
The Brain

Before 1960, the brain was considered by scientists to be immutable, subject only to genetic control. In the early sixties, however, investigators were seriously speculating that environmental influences might be capable of altering brain structure. By 1964, two research laboratories proved that the morphology and chemistry or physiology of the brain could be experientially altered (Bennett et al. 1964, Hubel and Wiesel 1965). Since then, the capacity of the brain to respond to environmental input, specifically "enrichment,'' has become an accepted fact among neuroscientists, educators and others. In fact, the demonstration that environmental enrichment can modify structural components of the rat brain at any age altered prevailing presumptions about the brain's plasticity (Diamond et al. 1964, Diamond 1988). The cerebral cortex, the area associated with higher cognitive processing, is more receptive than other parts of the brain to environmental enrichment. The message is clear: Although the brain possesses a relatively constant macrostructural organization, the ever-changing cerebral cortex, with its complex microarchitecture of unknown potential, is powerfully shaped by experiences before birth, during youth and, in fact, throughout life. It is essential to note that enrichment effects on the brain have consequences on behavior. Parents, educators, policy makers, and individuals can all benefit from such knowledge.

Skeletal muscle phosphofructokinase activity examined under physiological conditions in vitro

1995 ◽  
Vol 78 (5) ◽  
pp. 1853-1858 ◽  
Author(s):  
S. J. Peters ◽  
L. L. Spriet
Keyword(s):  
Skeletal Muscle ◽  
Aerobic Exercise ◽  
Potent Inhibitor ◽  
Maximal Activity ◽  
Physiological Conditions ◽  
In Vitro Measurements ◽  
Phosphofructokinase Activity ◽  
Regulatory Properties ◽  
Citrate Inhibition

The in vitro activity of skeletal muscle phosphofructokinase (PFK) was determined over the full physiological range of citrate concentrations. Enzyme aggregation was enhanced with a crowding agent, as the regulatory properties of PFK are altered with dilution. Cuvette conditions simulated concentrations of effectors and substrates during rest, moderate aerobic exercise, and intense aerobic exercise in human skeletal muscle. Citrate inhibition was not eliminated with enhanced enzyme aggregation, but activity was improved at all citrate concentrations. Maximal PFK activity with no citrate present was 0.27 +/- 0.01 mumol.min-1.mg-1 protein with resting effectors and 1.64 +/- 0.07 and 7.15 +/- 0.52 mumol.min-1.mg-1 protein with moderate aerobic and intense aerobic effector levels, respectively. Under resting conditions, PFK activity decreased to 49% of maximal when citrate was increased from 0 to 0.15 mM and only a small further inhibition to 43% occurred at 0.5 mM. Citrate was a less potent inhibitor under both exercise conditions with the sharpest decline to 72–77% of maximal activity at 0.15 mM followed by a slower decline to 65–70 and 53% activity at 0.25 and 0.5 mM citrate, respectively. The present in vitro measurements predict that alterations in citrate around concentrations normally reported in resting and exercising muscle would have little effect on flux through PFK. Therefore, the generally accepted concept that citrate is a potent inhibitor of PFK in all physiological situations has been exaggerated.

THE EFFECTS OF X-IRRADIATION ON PROTEIN METABOLISM OF THE BRAIN

1965 ◽  
Vol 43 (7) ◽  
pp. 1091-1098 ◽  
Author(s):  
Shozo Nakazawa ◽  
Takao Hara ◽  
Komei Ueki
Keyword(s):  
Rat Brain ◽  
Protein Metabolism ◽  
Leucine Incorporation ◽  
Adult Rats ◽  
Rat Brain And Liver ◽  
Glucose Incorporation ◽  
X Irradiation ◽  
Total Body ◽  
The Brain

The effects of X-irradiation on the metabolism of rat brain, liver, and spleen have been studied. C14-Glucose incorporation into protein of the brain of newborn rats was affected significantly by total body X-irradiation (250 r each day for 4 days). C14-Leucine incorporation into protein of the brain, liver, and spleen of adult rats was also reduced by total body X-irradiation (300 r each day for 4 days).X-irradiation of the head (500 r each day for 6 days) affected C14-leucine incorporation into protein of rat brain and liver, but it did not affect that of spleen.X-irradiation in vitro (5000 r) did not have any effect on protein metabolism of rat brain. The mode of action of X-irradiation on protein metabolism is discussed.

scholarly journals K+-p-nitrophenylphosphatase activity in rat brain and liver

2009 ◽  
pp. 121-126
Author(s):  
M Ďurfinová ◽  
M Brechtlová ◽  
B Líška ◽  
Ž Barošková
Keyword(s):  
Rat Brain ◽  
Brain Activity ◽  
Brain Homogenate ◽  
Whole Brain ◽  
Pellet Fraction ◽  
Total Brain ◽  
Rat Brain And Liver ◽  
Protein Rich ◽  
The Brain

K+-p-nitrophenylphosphatase (K+pNPPase) is the enzyme, which is considered to be involved in K+-dependent hydrolysis of the phosphoenzyme in the reaction cycle of Na+, K+-ATPase. The aim of our present study was to characterize some features of K+pNPPase in homogenates of the rat brain and liver. We determined p-nitrophenylphosphatase (pNPPase) activity in the presence of various ion combinations (Mg2++K+, Mg2+, K+). We found a higher total pNPPase activity in the brain (0.8±0.079 nkat/mg protein) than in the liver (0.08±0.01 nkat/mg protein). Contrary to the liver, the main part of the total brain activity was K+-dependent. The activity of K+pNPPase was significantly higher in cerebral cortex homogenates (0.86±0.073 nkat/mg protein) in comparison to those of the whole brain (0.57±0.075 nkat/mg protein). The specific K+pNPPase activity was two times higher in the isolated pellet fraction (0.911±0.07 nkat/mg protein), rich in synaptosomes, compared to the whole brain homogenate (0.57±0.075 nkat/mg protein). Our results demonstrate the high activity of K+pNPPase in the brain tissue and its distribution mainly into the pellet fraction, what might indicate a possible role of K+pNPPase in specific structures of the brain, e.g. in synaptosomes.

N-Acylation of tyramines: purification and characterization of an arylamine N-acetyltransferase from rat brain and liver

1979 ◽  
Vol 57 (10) ◽  
pp. 1204-1209 ◽  
Author(s):  
Peter H. Yu ◽  
Alan A. Boulton
Keyword(s):  
Monoamine Oxidase ◽  
Rat Brain ◽  
Kinetic Parameters ◽  
Biogenic Amines ◽  
Significant Activity ◽  
Purification And Characterization ◽  
Rat Brain And Liver ◽  
The Brain ◽  
Optimal Ph

The N-acylation of tyramine isomers and other biogenic amines has been studied. The liver exhibits the highest activity towards tyramines, while the brain exhibits a low but significant activity. In the brain, tyramine N-acylation activity was heterogenously distributed. The arylamine N-acetyltransferase has been partially purified from both rat liver and brain, the two enzymes being quite similar with respect to their chromatographic properties, optimal pH requirement (pH 7.8), and their kinetic parameters. The product N-acetyltyramine is not oxidized by liver amidohydrolase or monoamine oxidase.

scholarly journals Identiy of brain alcohol dehydrogenase with liver alcohol dehydrogenase

1976 ◽  
Vol 153 (3) ◽  
pp. 561-566 ◽  
Author(s):  
R J Duncan ◽  
J E Kline ◽  
L Sokoloff
Keyword(s):  
Alcohol Dehydrogenase ◽  
Rat Brain ◽  
Specific Activity ◽  
Liver Homogenate ◽  
Total Activity ◽  
Liver Alcohol Dehydrogenase ◽  
Rat Brain And Liver ◽  
Severe Liver Damage ◽  
Common Antigens ◽  
The Brain

A method for obtaining electrophoretically homogeneous rat liver alcohol dehydrogenase (EC 1.1.1.1) at a specific activity of 2-2.5 μmol/min per mg of protein is presented. Anti-sera prepared against the purified enzyme inhibit alcohol dehydrogenase by up to 75% and cause precipitation of virtually all the enzyme. The antisera were shown by immunoelectrophoresis of a partially purified liver homogenate to be specifically directed against alcohol dehydrogenase and were used to demonstrate that the alcohol dehydrogenases of rat brain and liver share common antigens. The total activity of alcohol dehydrogenase in rat brain homogenates is normally quite low, with as much as 10% of the total activity attributable to the activity in the blood contained within the brain; in cases of severe liver damage (induced experimentally with carbon tetrachloride) this contribution may rise to as much as 60%.

Endotoxin Alteration of the Mucopolysaccharide Blood Vessel Coating in Rats

1974 ◽  
Vol 32 ◽  
pp. 148-149
Author(s):  
D. E. Philpott ◽  
A. Takahashi
Keyword(s):  
Skeletal Muscle ◽  
Endothelial Cells ◽  
Salivary Gland ◽  
Carotid Artery ◽  
Basement Membrane ◽  
Coronary Vessels ◽  
Ruthenium Red ◽  
E Coli ◽  
Old Rats ◽  
The Brain

Two month, eight month and two year old rats were treated with 10 or 20 mg/kg of E. Coli endotoxin I. P. The eight month old rats proved most resistant to the endotoxin. During fixation the aorta, carotid artery, basil arartery of the brain, coronary vessels of the heart, inner surfaces of the heart chambers, heart and skeletal muscle, lung, liver, kidney, spleen, brain, retina, trachae, intestine, salivary gland, adrenal gland and gingiva were treated with ruthenium red or alcian blue to preserve the mucopolysaccharide (MPS) coating. Five, 8 and 24 hrs of endotoxin treatment produced increasingly marked capillary damage, disappearance of the MPS coating, edema, destruction of endothelial cells and damage to the basement membrane in the liver, kidney and lung.

Liquid Chromatography Analysis of Clozapine in Rat Brain Tissue, Using its Molecularly Imprinted Polymer after Administration of Toxic Dose of Drug and Lipid Emulsion Therapy

2019 ◽  
Vol 15 (3) ◽  
pp. 251-257
Author(s):  
Bahareh Sadat Yousefsani ◽  
Seyed Ahmad Mohajeri ◽  
Mohammad Moshiri ◽  
Hossein Hosseinzadeh
Keyword(s):  
Rat Brain ◽  
Brain Tissue ◽  
Molecularly Imprinted Polymer ◽  
Lipid Emulsion ◽  
Limit Of Detection ◽  
Imprinted Polymer ◽  
Toxic Dose ◽  
Molecularly Imprinted ◽  
The Brain ◽  
Rat Brain Tissue

Background:Molecularly imprinted polymers (MIPs) are synthetic polymers that have a selective site for a given analyte, or a group of structurally related compounds, that make them ideal polymers to be used in separation processes.Objective:An optimized molecularly imprinted polymer was selected and applied for selective extraction and analysis of clozapine in rat brain tissue.Methods:A molecularly imprinted solid-phase extraction (MISPE) method was developed for preconcentration and cleanup of clozapine in rat brain samples before HPLC-UV analysis. The extraction and analytical process was calibrated in the range of 0.025-100 ppm. Clozapine recovery in this MISPE process was calculated between 99.40 and 102.96%. The limit of detection (LOD) and the limit of quantification (LOQ) of the assay were 0.003 and 0.025 ppm, respectively. Intra-day precision values for clozapine concentrations of 0.125 and 0.025 ppm were 5.30 and 3.55%, whereas inter-day precision values of these concentrations were 9.23 and 6.15%, respectively. In this study, the effect of lipid emulsion infusion in reducing the brain concentration of drug was also evaluated.Results:The data indicated that calibrated method was successfully applied for the analysis of clozapine in the real rat brain samples after administration of a toxic dose to animal. Finally, the efficacy of lipid emulsion therapy in reducing the brain tissue concentration of clozapine after toxic administration of drug was determined.Conclusion:The proposed MISPE method could be applied in the extraction and preconcentration before HPLC-UV analysis of clozapine in rat brain tissue.

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