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%.

DNA Polymerases of Newborn Rat Brain and Liver

1971 ◽  
Vol 49 (8) ◽  
pp. 978-986 ◽  
Author(s):  
A. D. Bharucha ◽  
M. R. V. Murthy
Keyword(s):  
Rat Brain ◽  
Specific Activity ◽  
Hydrolytic Enzymes ◽  
Polymerase Activity ◽  
Newborn Rat ◽  
Newborn Brain ◽  
Rat Brain And Liver ◽  
Mammalian Tissues ◽  
Optimum Ph ◽  
Sulfhydryl Compounds

DNA polymerase activity was found to be present in appreciable quantities in the extracts of whole tissue (TS) as well as of nuclei (NS) isolated from newborn rat brain and liver. The NS fractions of either of the two tissues exhibited a higher specific activity per unit protein than the corresponding TS fractions. The optimum pH requirements as well as the ability to support DNA synthesis over a long period indicate that the NS fractions were also comparatively less contaminated by interfering substances than the TS fractions.The reaction requirements for the incorporation of TMP residues into DNA by the NS fractions of newborn rat brain and liver and the effect of various inhibitors and hydrolytic enzymes on this reaction were also investigated. These extracts resembled preparations from other mammalian tissues in that they exhibited absolute requirements for the primer DNA, the four complimentary deoxynucleoside triphosphates, and Mg2+ ions. When three of the four deoxynucleoside triphosphates were omitted and only TTP-2-14C was added to the reaction mixture, a limited incorporation of TMP-2-14C into DNA occurred. Other investigations such as the effect of actinomycin and of sulfhydryl compounds revealed that a large part of incorporation by the TS and NS fractions of newborn brain and liver was due to the replicative DNA nucleotidyltransferase enzyme.

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.

Sodium Nitrite Alone Protects the Brain Microsomal Ca2+-ATPase Against Potassium Cyanide-induced Neurotoxicity In Rats

1997 ◽  
Vol 17 (6) ◽  
pp. 543-546 ◽  
Author(s):  
O. O. Odunuga ◽  
G. A. Adenuga
Keyword(s):  
Oral Administration ◽  
Atpase Activity ◽  
Rat Brain ◽  
Sodium Nitrite ◽  
Specific Activity ◽  
Potassium Cyanide ◽  
Protective Role ◽  
Short Term ◽  
Significant Difference ◽  
The Brain

The effect of a short-term oral administration of potassium cyanide (KCN) (200 ppm in diet) with or without sodium nitrite (NaNO2) pretreatment on rat brain microsomal Ca2± ATPase was investigated. The specific activity value of the enzyme significantly decreased (p<0.05) by 50% compared with control and by 63% for KCN-treated rats compared with KCN-treated rats pretreated with NaNO2. There was no significant difference at the h=0.05 level between the values obtained for the control and KCN-treated rats pretreated with NaNO2. These results show both that feeding lowers brain microsomal Ca2+-ATPase activity and that NaNO2 has a protective role (antidote function) in that respect.

scholarly journals Regional Cerebral l-[14C-Methyl]Methionine Incorporation into Proteins: Evidence for Methionine Recycling in the Rat Brain

1992 ◽  
Vol 12 (4) ◽  
pp. 603-612 ◽  
Author(s):  
Anna M. Planas ◽  
Christian Prenant ◽  
Bernard M. Mazoyer ◽  
Dominique Comar ◽  
Luigi Di Giamberardino
Keyword(s):  
Rat Brain ◽  
Specific Activity ◽  
Plasma Source ◽  
Brain Regions ◽  
Emission Tomography ◽  
Protein Breakdown ◽  
Isotopic Equilibrium ◽  
Positron Emission ◽  
Time Periods ◽  
The Brain

The specific activity (SA) of free methionine was measured in plasma and in different regions of the rat brain at 15, 30, or 60 min after intravenous infusion of l-[14C- methyl]methionine. Within these time periods, an apparent steady state of labeled free methionine in plasma and in brain was reached. However, the brain-to-plasma free methionine SA ratio was found to be ∼0.5, showing that an isotopic equilibrium between brain and plasma was not attained. This suggests the presence of an endogenous source of brain free methionine (likely originating from protein breakdown), in addition to the plasma source. The contribution of this endogenous source to the content of free methionine varies significantly among the different brain regions. Our results indicate that the regional rates of protein synthesis measured with l-[11C- methyl]methionine using positron emission tomography would be underestimated, since the local fraction of brain methionine derived from protein degradation would not be considered.

Depolymerization of polyadenylic acid by subcellular fractions of rat brain and liver

1969 ◽  
Vol 47 (3) ◽  
pp. 283-289 ◽  
Author(s):  
M. R. V. Murthy ◽  
A. D. Bharucha ◽  
C. Raynaud-Jammet
Keyword(s):  
Rat Brain ◽  
Microsomal Fraction ◽  
Soluble Fraction ◽  
Total Activity ◽  
Relative Increase ◽  
Nuclear Fraction ◽  
Polyadenylic Acid ◽  
Rat Brain And Liver ◽  
Liver Homogenates ◽  
Maximum Increment

Rat brain and liver homogenates depolymerized polyadenylic acid when added to a reaction mixture containing this polynucleotide. The activity in the homogenate declined progressively with the age of the tissues. This was reflected in a parallel reduction in the activity of the soluble fraction. In brain, the activity in the nuclear fraction also declined in the adult to half the level of the newborn. In contrast, liver nuclei had approximately the same activity at all stages of growth.With advancement in age, an increasingly greater proportion of the total activity of the tissues was contained in the nuclear fraction, while at the same time the proportion of activity in the soluble fraction decreased. The proportion of activity contained in the mitochondrial–microsomal fraction also increased with growth in brain, with the maximum increment in activity occurring after 8 weeks of age. In liver, there was actually a decrease of activity in this fraction during the same period. At all ages, the mitochondrial–microsomal fraction of brain contained a higher proportion of activity and the nuclear fraction of brain contained a lower proportion of activity compared to corresponding fractions of liver. The presence of polyadenylic acid degrading activity in these fractions and its relative increase with age may indicate a changing emphasis in the pattern of RNA metabolism during growth; for example, a higher rate of RNA synthesis in the young and a higher rate of RNA turnover in the adult.When the soluble fraction of rat brain was dialyzed, the polyadenylic acid degrading activity of this fraction was stimulated by the addition of inorganic orthophosphate. Brain and liver homogenates also mediated an ADP – inorganic phosphate exchange reaction which was highest in the newborn and decreased rapidly with age. These observations indicate that at least a part of the polyadenylic acid degrading activity in brain and liver extracts may be due to phosphorolytic action.

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.

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.

AN ATYPICAL HUMAN ALCOHOL DEHYDROGENASE

1965 ◽  
Vol 43 (7) ◽  
pp. 889-898 ◽  
Author(s):  
J.-P. von Wartburg ◽  
J. Papenberg ◽  
H. Aebi
Keyword(s):  
Alcohol Dehydrogenase ◽  
Metal Binding ◽  
Liver Homogenate ◽  
Liver Alcohol Dehydrogenase ◽  
Alcohol Dehydrogenase Activity ◽  
Normal Human Liver ◽  
Total Alcohol ◽  
Normal Human ◽  
Human Livers ◽  
Rate Profile

An atypical alcohol dehydrogenase was found in two human livers. The anomalous enzyme, which has been purified, differs from the normal regarding (a) pH rate profile, (b) substrate specificity, and (c) sensitivity to metal binding agents. Thiourea inhibits the variant enzyme, but activates normal human liver alcohol dehydrogenase. A simple screening test is described to differentiate between atypical and normal alcohol dehydrogenase in liver homogenate. Total alcohol dehydrogenase activity was considerably higher in livers containing the atypical enzyme.

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