Activities of the phosphatidylcholine biosynthetic enzymes in rat liver during development

1983 ◽  
Vol 61 (10) ◽  
pp. 1147-1152 ◽  
Author(s):  
Steven L. Pelech ◽  
Ellen Power ◽  
Dennis E. Vance
Keyword(s):  
Enzyme Activity ◽  
Rat Liver ◽  
Specific Activity ◽  
Perinatal Period ◽  
Choline Kinase ◽  
Specific Enzyme ◽  
Methyltransferase Activity ◽  
Specific Enzyme Activity ◽  
Ctp:Phosphocholine Cytidylyltransferase ◽  
Phosphatidylcholine Biosynthesis

The activities of the enzymes of rat hepatic phosphatidylcholine biosynthesis have been measured as a function of development in the rat (term, 23 days). During the last 5 days of gestation, the specific activity of choline kinase was elevated almost fivefold (p < 0.05). After parturition, choline kinase activity was reduced to adult values by the 5th postnatal day. Over 75% of the total CTP:phosphocholine cytidylyltransferase protein in prenatal liver was detected in the cytosolic fraction. On the day of birth, most of the cytidylyltransferase translocated to the microsomes so that the microsomal specific enzyme activity was 3.3-fold higher (p < 0.01) and the cytosolic specific enzyme activity (measured in the presence of phospholipid) was 68% lower (p < 0.001) than the day before parturition. CDPcholine:diacylglycerol cholinephosphotransferase activity (measured in the presence of diacylglycerol) increased 130-fold (p < 0.001) during the last 5 days of gestation. On the 10th postnatal day, cholinephosphotransferase activity was 1.7-fold higher (p < 0.001) than immediately after birth, but declined to adult values by the 19th day. Between the 5th day prior to parturition and the 10th postnatal day, phosphatidylethanolamine N-methyltransferase activity steadily increased 16-fold (p < 0.001). The results are in agreement with the hypothesis that the increase in phosphatidylcholine in rat liver during the perinatal period is due to an increased synthesis of CDPcholine, which is a consequence of the translocation of the cytidylyltransferase from cytosol to the endoplasmic reticulum.

scholarly journals Magnetically Agitated Nanoparticle-Based Batch Reactors for Biocatalysis with Immobilized Aspartate Ammonia-Lyase

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 483
Author(s):  
Ali Obaid Imarah ◽  
Pál Csuka ◽  
Naran Bataa ◽  
Balázs Decsi ◽  
Evelin Sánta-Bell ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Permanent Magnets ◽  
Specific Activity ◽  
Covalent Binding ◽  
Batch Reactors ◽  
Specific Enzyme ◽  
Specific Enzyme Activity ◽  
Effective Activity ◽  
Functionalized Magnetic Nanoparticles ◽  
Magnetic Mixing

In this study, we investigated the influence of different modes of magnetic mixing on effective enzyme activity of aspartate ammonia-lyase from Pseudomonas fluorescens immobilized onto epoxy-functionalized magnetic nanoparticles by covalent binding (AAL-MNP). The effective specific enzyme activity of AAL-MNPs in traditional shake vial method was compared to the specific activity of the MNP-based biocatalyst in two devices designed for magnetic agitation. The first device agitated the AAL-MNPs by moving two permanent magnets at two opposite sides of a vial in x-axis direction (being perpendicular to the y-axis of the vial); the second device unsettled the MNP biocatalyst by rotating the two permanent magnets around the y-axis of the vial. In a traditional shake vial, the substrate and biocatalyst move in the same direction with the same pattern. In magnetic agitation modes, the MNPs responded differently to the external magnetic field of two permanent magnets. In the axial agitation mode, MNPs formed a moving cloud inside the vial, whereas in the rotating agitation mode, they formed a ring. Especially, the rotating agitation of the MNPs generated small fluid flow inside the vial enabling the mixing of the reaction mixture, leading to enhanced effective activity of AAL-MNPs compared to shake vial agitation.

scholarly journals Reconstitution of purified Wistar rat liver bilirubin UDP-glucuronyltransferase into Gunn-rat liver microsomes

1982 ◽  
Vol 201 (3) ◽  
pp. 653-656 ◽  
Author(s):  
B Burchell
Keyword(s):  
Enzyme Activity ◽  
Rat Liver ◽  
Specific Activity ◽  
Liver Microsomes ◽  
Wistar Rat ◽  
Transferase Activity ◽  
Rat Liver Microsomes ◽  
Phosphatidylcholine Liposomes ◽  
Gunn Rat ◽  
Rigid Environment

1. Reconstitution of purified bilirubin UDP-glucuronyltransferase from Wistar-rat liver into Gunn-rat liver microsomes provides a better environment than phosphatidylcholine liposomes, such that the final specific activity of the Wistar-rat liver enzyme was increased up to 85 units/mg of protein. 2. Gunn- and Wistar-rat liver microsomes were equally effective for reconstitution of the purified enzyme. 3. The transferase activity does not appear to be fully expressed in the more rigid environment of foetal Wistar-rat liver microsomes. 4. These reconstitution experiments reveal a final specific activity for the purified bilirubin UDP-glucuronyltransferase consistent with the capacity of the whole rat liver to glucuronidate bilirubin and indicate that the absence of this enzyme activity in Gunn-rat liver microsomes is not due to an abnormal microenvironment.

A new bilirubin-degrading enzyme from orange peels

1988 ◽  
Vol 66 (11) ◽  
pp. 1248-1252 ◽  
Author(s):  
Tai-Wing Wu ◽  
Grace S. Li
Keyword(s):  
Enzyme Activity ◽  
Absorption Spectrum ◽  
Cholic Acid ◽  
Rat Liver ◽  
Specific Activity ◽  
Unconjugated Bilirubin ◽  
Proteinase K ◽  
Bilirubin Oxidase ◽  
Orange Peels ◽  
Poorly Soluble

A novel enzyme activity that catalyzes the degradation of unconjugated bilirubin (Bu) has been demonstrated in extracts of the peels of edible oranges. Unlike the few known bilirubin-oxidizing enzymes, the orange enzyme does not produce biliverdin as a product, does not seem to require oxygen, and has a unique absorption spectrum of its products. Even at the crude stage, the enzyme has a specific activity that is 10 and 20 times higher, respectively, than those reported for the crude or partially purified Bu-degrading enzymes from mushrooms and rat liver. The enzyme has apH optimum near 7.5 and a Km value of 50–100 μM for Bu. The enzyme is remarkably stable, retaining over 50% activity after prolonged digestion with proteinase K or heating at 100 °C. Similar treatments inactivated the bilirubin oxidase from Myrothecium verrucaria MT-1. The enzyme is poorly soluble in water but can be partially solubilized with cholic acid, with a doubling in specific activity.

Specific Enzyme Activity

2019 ◽  
Author(s):  
Ján Labuda ◽  
Richard P. Bowater ◽  
Miroslav Fojta ◽  
Günter Gauglitz ◽  
Zdeněk Glatz ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Specific Enzyme ◽  
Specific Enzyme Activity

scholarly journals Preparation of gram quantities of a purified R-factor-mediated penicillinase from Escherichia coli strain W3310

1972 ◽  
Vol 130 (1) ◽  
pp. 55-62 ◽  
Author(s):  
J. Melling ◽  
G. K. Scott
Keyword(s):  
Escherichia Coli ◽  
Molecular Weight ◽  
Enzyme Activity ◽  
Coli Strain ◽  
Specific Enzyme ◽  
Specific Enzyme Activity ◽  
E Coli ◽  
R Factor

Purified penicillinase, in gram quantities, has been prepared from Escherichia coli strain W3310 by using methods developed to handle large amounts of material. The final product had a specific enzyme activity of 3.08 units/μg of protein, which was over twice as high as that reported previously (Datta & Richmond, 1966). The purified enzyme was similar to that from E. coli strain TEM, but different in molecular weight and some other respects. The differences observed may be a result of the greater purity obtained.

Detection in HeLa cell extracts of a 7-methyl guanosine specific enzyme activity that cleaves m7GpppNm

Cell ◽  
1975 ◽  
Vol 6 (1) ◽  
pp. 21-27 ◽  
Author(s):  
D.L. Nuss ◽  
Y. Furuichi ◽  
G. Koch ◽  
A.J. Shatkin
Keyword(s):  
Enzyme Activity ◽  
Hela Cell ◽  
Specific Enzyme ◽  
Specific Enzyme Activity ◽  
Cell Extracts

scholarly journals N-[2-bromocinnamyl(amino)ethyl]-5-isoquinolinesulphonamide (H-89) inhibits incorporation of choline into phosphatidylcholine via inhibition of choline kinase and has no effect on the phosphorylation of CTP:phosphocholine cytidylyltransferase

1994 ◽  
Vol 297 (1) ◽  
pp. 241-247 ◽  
Author(s):  
M Wieprecht ◽  
T Wieder ◽  
C C Geilen
Keyword(s):  
Cell Culture ◽  
Kinase Activity ◽  
Inhibitory Effect ◽  
Selective Inhibitor ◽  
Choline Kinase ◽  
Dependent Protein Kinase ◽  
Ctp:Phosphocholine Cytidylyltransferase ◽  
Phosphatidylcholine Biosynthesis ◽  
Dependent Protein

We have shown previously that N-[2-bromocinnamyl(amino)-ethyl]-5-isoquinolinesulphonamide (H-89), a selective inhibitor of cyclic-AMP-dependent protein kinase (PKA), inhibits phosphatidylcholine biosynthesis in HeLa cells. In the present study, we elucidated the mechanism underlying the described inhibition. Treatment of cells with 10 microM H-89 had no effect on the phosphorylation of CTP:phosphocholine cytidylyltransferase. However, H-89 slightly affected the distribution of cytidylyltransferase between cytosol and membranes, but the cellular 1,2-diacylglycerol content was not influenced. Furthermore, pulse-chase experiments revealed that H-89 did not affect cytidylyltransferase activity. Instead, H-89 inhibited choline kinase, the enzyme catalysing the first step in the CDP-choline pathway. In the presence of 10 microM H-89, choline kinase activity was inhibited by 36 +/- 7.6% in vitro. Additionally, the phosphorylation of choline to phosphocholine was inhibited by 30 +/- 3% in cell-culture experiments. This inhibitory effect could be partly prevented by simultaneous addition of 10 microM forskolin, indicating that choline kinase is regulated in part by PKA activity.

scholarly journals Intracellular enzymes of collagen biosynthesis in rat liver as a function of age and in hepatic injury induced by dimethylnitrosamine. Purification of rat prolyl hydroxylase and comparison of changes in prolyl hydroxylase activity with changes in immunoreactive prolyl hydroxylase

1976 ◽  
Vol 158 (2) ◽  
pp. 369-376 ◽  
Author(s):  
J Risteli ◽  
L Tuderman ◽  
K I Kivirikko
Keyword(s):  
Enzyme Activity ◽  
Rat Liver ◽  
Hepatic Injury ◽  
Specific Activity ◽  
Prolyl Hydroxylase ◽  
Newborn Rats ◽  
Hydroxylase Activity ◽  
Immunoreactive Protein ◽  
Molecular Weights ◽  
Polypeptide Chains

Prolyl hydroxylase was purified from newborn rats by affinity chromatography using poly(L-proline), and antiserum to the enzyme was prepared in rabbits. The rat prolyl hydroxylase was similar to the chick and human enzymes with respect to specific activity, molecular weight and molecular weights of the polypeptide chains. The activity of prolyl hydroxylase and the content of immunoreactive enzyme were measured in rat liver as a function of age in experimental hepatic injury. Active prolyl hydroxylase comprised about 13.2% of the total immunoreactive protein in the liver of newborn rats and the value decreased to about 3.6% at the age of 420 days. This decrease was due to a decrease in the enzyme activity, whereas only minor changes were found in the content of the immunoreactive protein. In hepatic injury, a significant increase was found in the ratio of active enzyme to total immunoreactive protein, owing to an increase in the enzyme activity. The data indicate that prolyl hydroxylase activity in rat liver is controlled in part by a mechanism which does not involve changes in the content of the total immunoreactive protein.

scholarly journals The effect of phenobarbital on the submicrosomal distribution of uridine diphosphate glucuronyltransferase from rat liver

1970 ◽  
Vol 117 (2) ◽  
pp. 319-324 ◽  
Author(s):  
G. J. Mulder
Keyword(s):  
Enzyme Activity ◽  
Density Gradient ◽  
Rat Liver ◽  
Microsomal Fraction ◽  
Specific Activity ◽  
Sucrose Density Gradient ◽  
Male Rats ◽  
Uridine Diphosphate ◽  
Triton X

1. The detergent Triton X-100 activates UDP glucuronyltransferase from rat liver in vitro six- to seven-fold with p-nitrophenol as substrate. The enzyme activity when measured in the presence of Triton X-100 is increased significantly by pretreatment of male rats with phenobarbital for 4 days (90mg/kg each day intraperitoneally). If no Triton X-100 is applied in vitro such an increase could not be shown. In all further experiments the enzyme activity was measured after activation by Triton X-100. 2. The Km of the enzyme for the substrate p-nitrophenol does not change on phenobarbital pretreatment. 3. When the microsomal fraction from the liver of untreated rats is subfractionated on a sucrose density gradient, 47% of the enzyme activity is recovered in the rough-surfaced microsomal fraction, which also has a higher specific activity than the smooth-surfaced fraction. 4. Of the increase in activity after the phenobarbital pretreatment 50% occurs in the smooth-surfaced fraction, 19% in the rough-surfaced fraction and 31% in the fraction located between the smooth- and rough-surfaced microsomal fractions on the sucrose density gradient. 5. The latency of the enzyme in vitro, as shown by the effect of the detergent Triton X-100, is discussed in relation to the proposed heterogeneity of UDP glucuronyltransferase.

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