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.

DNA Polymerase Activity in the Nuclei of Developing Rat Brain and Liver

1972 ◽  
Vol 50 (2) ◽  
pp. 186-189 ◽  
Author(s):  
M. R. V. Murthy ◽  
A. D. Bharucha
Keyword(s):  
Rat Brain ◽  
Dna Polymerase ◽  
Soluble Fraction ◽  
Growth Period ◽  
Polymerase Activity ◽  
Newborn Rat ◽  
A Value ◽  
Rat Brain And Liver ◽  
Dna Contents ◽  
Developing Rat

The level of DNA polymerase activity per tissue in the soluble fraction (NS) of rat brain nuclei underwent a twofold increase during the first 2 weeks after birth and then declined steeply over the next 10 weeks to a value only one-third ofthat in the newborn. In contrast to brain, the enzyme activity per liver increased continuously from birth up to 12 weeks of age (10-fold). The DNA contents of these tissues appear to be quantitatively related to the DNA polymerase activities in the respective NS fractions. These preparations did not phosphorylate thymidylate to TTP, but could convert the other three complementary deoxynucleotides to the triphosphate level. This latter activity was highest in the NS fraction of the newborn rat brain and decreased drastically with growth. In the corresponding fraction of liver, the activity remained relatively stable throughout the growth period tested.

Deoxyribonucleic Acid Polymerase of Trout Liver Nuclei

1970 ◽  
Vol 27 (1) ◽  
pp. 117-123 ◽  
Author(s):  
H. L. A. Tarr ◽  
Linda Gardner
Keyword(s):  
Dna Polymerase ◽  
Specific Activity ◽  
Polymerase Activity ◽  
Freezing And Thawing ◽  
Low Concentrations ◽  
Mandatory Requirement ◽  
Mammalian Tissues ◽  
Liver Nuclei ◽  
Deoxynucleoside Triphosphate ◽  
High Concentrations

The DNA polymerase of intact trout liver nuclei behaved similarly to that present in mammalian tissues in its mandatory requirement for four deoxynucleoside triphosphates, Mg2+, and DNA primer. It was inhibited by DNase and pyrophosphate in comparatively low concentrations and by RNase and Actinomycin D in comparatively high concentrations. Soluble DNA polymerase was extracted from buffered suspensions of the nuclei by centrifugation at 100,000 g. It possessed properties very similar to those exhibited by the enzyme in intact nuclei. The polymerase activity of intact nuclei was increased by freezing and thawing, and the soluble enzyme was unstable at 30 C and lost most of its activity in 1 day at 0 C. The specific activity of the enzyme was 10–29 picomoles of deoxynucleoside triphosphate incorporated into DNA by 1 mg of protein in 1 hr at 25 C.

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%.

scholarly journals Enzymic synthesis of ether types of choline and ethanolamine phosphoglycerides by microsomal fractions from rat brain and liver

1977 ◽  
Vol 18 (1) ◽  
pp. 53-58
Author(s):  
A Radominska-Pyrek ◽  
J Strosznajder ◽  
Z Dabrowiecki ◽  
G Goracci ◽  
T Chojnacki ◽  
...  
Keyword(s):  
Rat Brain ◽  
Enzymic Synthesis ◽  
Ethanolamine Phosphoglycerides ◽  
Rat Brain And Liver

Respiration of Rat Brain and Liver at Temperatures above 37°C

1951 ◽  
Vol 24 (2) ◽  
pp. 163-166
Author(s):  
Robert L. Jasper ◽  
James W. Archdeacon
Keyword(s):  
Rat Brain ◽  
Rat Brain And Liver

scholarly journals Thermostable glucose isomerase from psychrotolerant Streptomyces species

1970 ◽  
Vol 1 ◽  
pp. 6-10 ◽  
Author(s):  
Bidur Dhungel ◽  
Manoj Subedi ◽  
Kiran Babu Tiwari ◽  
Upendra Thapa Shrestha ◽  
Subarna Pokhrel ◽  
...  
Keyword(s):  
Specific Activity ◽  
Fold Increase ◽  
Glucose Isomerase ◽  
Enzyme Concentration ◽  
Maximal Velocity ◽  
Ph Optimum ◽  
Streptomyces Spp ◽  
Optimum Ph ◽  
Optimum Reaction ◽  
Sepharose 4B

Glucose isomerase (EC 5.3.1.5) was extracted from Streptomyces spp., isolated from Mt. Everest soil sample, and purified by ammonium sulfate fractionation and Sepharose-4B chromatography. A 7.1 fold increase in specific activity of the purified enzyme over crude was observed. Using glucose as substrate, the Michaelis constant (KM<) and maximal velocity (Vmax) were found to be 0.45M and 0.18U/mg. respectively. The optimum substrate (glucose) concentration, optimum enzyme concentration, optimum pH, optimum temperature, and optimum reaction time were 0.6M, 62.14μg/100μl, 6.9, 70ºC, and 30 minutes, respectively. Optimum concentrations of Mg2+ and Co2+ were 5mM and 0.5mM, respectively. The enzyme was thermostable with half-life 30 minutes at 100ºC.DOI: 10.3126/ijls.v1i0.2300 Int J Life Sci 1 : 6-10

ENZYMIC CHANGES IN THE CERVIX OF THE RAT AND HAMSTER DURING THE OESTROUS CYCLE AND THE EFFECT OF STEROIDS

1977 ◽  
Vol 72 (2) ◽  
pp. 153-161 ◽  
Author(s):  
ELIZABETH ZACHARIAH ◽  
N. R. MOUDGAL
Keyword(s):  
Alkaline Phosphatase ◽  
Specific Activity ◽  
Protein Biosynthesis ◽  
Hydrolytic Enzymes ◽  
Maximal Activity ◽  
Inhibitory Effect ◽  
Oestrous Cycle ◽  
Single Subcutaneous Injection ◽  
Arylsulphatase A ◽  
Phosphatase Alkaline

SUMMARY Changes in four hydrolytic enzymes, namely acid phosphatase, alkaline phosphatase, arylsulphatase A and B, of the cervix of the rat and hamster have been studied during the 4-day oestrous cycle. All four enzymes showed maximal activity on the day of oestrus and least activity on day 2 of dioestrus. All the enzymes showed significant reduction of activity after ovariectomy, arylsulphatase A and B showing the earliest changes in specific activity. A single subcutaneous injection of 0·02 μg oestradiol-17β/rat increased the specific activity of arylsulphatase A and B from the low ovariectomized level to that observed in control oestrous animals within 18 and 6 h respectively. A higher concentration of oestradiol-17β (2·0 μg) had an inhibitory effect. Progesterone was without effect on arylsulphatase B activity, but when given (2·0 mg) with 0·02 μg oestradiol-17β, it inhibited the response to oestrogen. Cycloheximide prevented the rise in arylsulphatase B activity occurring after oestrogen injection, suggesting a regulation of cervical arylsulphatase B at the level of protein biosynthesis. These results suggest that arylsulphatase B activity may be induced by oestrogen in the cervix of the rat.

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