TY  - JOUR
AU  - Laketa, Danijela
AU  - Savić, Jasmina
AU  - Bjelobaba, Ivana
AU  - Lavrnja, Irene
AU  - Vasić, Vesna M.
AU  - Stojiljković, Mirjana
AU  - Nedeljković, Nadežda
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/385
AB  - Background: Cortical stab injury (CSI) induces changes in the activity, expression and cellular distribution of specific ectonucleotidases at the injury site. Also, several experimentally induced neuropathologies are associated with changes in soluble ectonucleotidase activities in the plasma and serum, whilst various insults to the brain alter purine compounds levels in cerebrospinal fluid, but also in serum, indicating that insults to the brain may induce alterations in nucleotides release and rate of their hydrolysis in the vascular system. Since adenine nucleotides and adenosine regulate diverse cellular functions in the vascular system, including vascular tone, platelet aggregation and inflammatory responses of lymphocytes and macrophages, alterations of ectonucleotidase activities in the vascular system may be relevant for the clinical outcome of the primary insult. Methods: We explored ectonucleotidase activities using specific enzyme assays and determined adenine nucleotides concentrations by the UPLC method in the rat serum after cortical stab injury. Results: At 4-h post-injury, ATP and AMP hydrolysis increased by about 60% and 40%, respectively, while phosphodiesterase activity remained unchanged. Also, at 4-h postinjury a marked decrease in ATP concentration and more than 2-fold increase in AMP concentration were recorded. Conclusions: CSI induces rapid up-regulation of nucleotide catabolizing soluble ectonucleotidases in rat serum, which leads to the observed shift in serum nucleotide levels. The results obtained imply that ectonucleotidases and adenine nucleotides participate in the communication between the brain and the vascular system in physiological and pathological conditions and thereby may be involved in the development of various human neuropathologies.
T2  - Journal of Medical Biochemistry
T1  - Brain Injury Alters Ectonucleotidase Activities and Adenine Nucleotide Levels in Rat Serum
VL  - 34
IS  - 2
SP  - 215
EP  - 222
DO  - 10.2478/jomb-2014-0025
ER  - 

@article{
author = "Laketa, Danijela and Savić, Jasmina and Bjelobaba, Ivana and Lavrnja, Irene and Vasić, Vesna M. and Stojiljković, Mirjana and Nedeljković, Nadežda",
year = "2015",
abstract = "Background: Cortical stab injury (CSI) induces changes in the activity, expression and cellular distribution of specific ectonucleotidases at the injury site. Also, several experimentally induced neuropathologies are associated with changes in soluble ectonucleotidase activities in the plasma and serum, whilst various insults to the brain alter purine compounds levels in cerebrospinal fluid, but also in serum, indicating that insults to the brain may induce alterations in nucleotides release and rate of their hydrolysis in the vascular system. Since adenine nucleotides and adenosine regulate diverse cellular functions in the vascular system, including vascular tone, platelet aggregation and inflammatory responses of lymphocytes and macrophages, alterations of ectonucleotidase activities in the vascular system may be relevant for the clinical outcome of the primary insult. Methods: We explored ectonucleotidase activities using specific enzyme assays and determined adenine nucleotides concentrations by the UPLC method in the rat serum after cortical stab injury. Results: At 4-h post-injury, ATP and AMP hydrolysis increased by about 60% and 40%, respectively, while phosphodiesterase activity remained unchanged. Also, at 4-h postinjury a marked decrease in ATP concentration and more than 2-fold increase in AMP concentration were recorded. Conclusions: CSI induces rapid up-regulation of nucleotide catabolizing soluble ectonucleotidases in rat serum, which leads to the observed shift in serum nucleotide levels. The results obtained imply that ectonucleotidases and adenine nucleotides participate in the communication between the brain and the vascular system in physiological and pathological conditions and thereby may be involved in the development of various human neuropathologies.",
journal = "Journal of Medical Biochemistry",
title = "Brain Injury Alters Ectonucleotidase Activities and Adenine Nucleotide Levels in Rat Serum",
volume = "34",
number = "2",
pages = "215-222",
doi = "10.2478/jomb-2014-0025"
}

Laketa, D., Savić, J., Bjelobaba, I., Lavrnja, I., Vasić, V. M., Stojiljković, M.,& Nedeljković, N.. (2015). Brain Injury Alters Ectonucleotidase Activities and Adenine Nucleotide Levels in Rat Serum. in Journal of Medical Biochemistry, 34(2), 215-222.
https://doi.org/10.2478/jomb-2014-0025

Laketa D, Savić J, Bjelobaba I, Lavrnja I, Vasić VM, Stojiljković M, Nedeljković N. Brain Injury Alters Ectonucleotidase Activities and Adenine Nucleotide Levels in Rat Serum. in Journal of Medical Biochemistry. 2015;34(2):215-222.
doi:10.2478/jomb-2014-0025 .

Laketa, Danijela, Savić, Jasmina, Bjelobaba, Ivana, Lavrnja, Irene, Vasić, Vesna M., Stojiljković, Mirjana, Nedeljković, Nadežda, "Brain Injury Alters Ectonucleotidase Activities and Adenine Nucleotide Levels in Rat Serum" in Journal of Medical Biochemistry, 34, no. 2 (2015):215-222,
https://doi.org/10.2478/jomb-2014-0025 . .

TY  - JOUR
AU  - Laketa, Danijela
AU  - Bjelobaba, Ivana
AU  - Savić, Jasmina
AU  - Lavrnja, Irena
AU  - Stojiljković, Mirjana
AU  - Rakić, Ljubisav
AU  - Nedeljković, Nadežda
PY  - 2010
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/3996
AB  - Biochemical properties of nucleotide pyrophosphatase/phosphodiesterase (NPP) in rat serum have been described by assessing its nucleotide phosphodiesterase activity, using p-nitrophenyl-5-thymidine monophosphate (p-Nph-5-TMP) as a substrate. It was demonstrated that NPP activity shares some typical characteristics described for other soluble NPP, such as divalent cation dependence, strong alkaline pH optimum (pH 10.5), inhibition by glycosaminoglycans, and K (m) for p-Nph-5-TMP hydrolysis of 61.8 +/- A 5.2 mu M. In order to characterize the relation between phosphodiesterase and pyrophosphatase activities of NPP, we have analyzed the effects of different natural nucleotides and nucleotide analogs. ATP, ADP, and AMP competitively inhibited p-Nph-5-TMP hydrolysis with K (i) values ranging 13-43 mu M. Nucleotide analogs, alpha,beta-metATP, BzATP, 2-MeSATP, and dialATP behaved as competitive inhibitors, whereas alpha,beta-metADP induced mixed inhibition, with K (i) ranging from 2 to 20 mu M. Chromatographic analysis revealed that alpha,beta-metATP, BzATP, and 2-MeSATP were catalytically degraded in the serum, whereas dialATP and alpha,beta-metADP resisted hydrolysis, implying that the former act as substrates and the latter as true competitive inhibitors of serum NPP activity. Since NPP activity is involved in generation, breakdown, and recycling of extracellular adenine nucleotides in the vascular compartment, the results suggest that both hydrolyzable and non-hydrolyzable nucleotide analogs could alter the amplitude and direction of ATP actions and could have potential therapeutic application.
T2  - Molecular and Cellular Biochemistry
T1  - Biochemical characterization of soluble nucleotide pyrophosphatase/phosphodiesterase activity in rat serum
VL  - 339
IS  - 1-2
SP  - 99
EP  - 106
DO  - 10.1007/s11010-009-0373-1
ER  - 

@article{
author = "Laketa, Danijela and Bjelobaba, Ivana and Savić, Jasmina and Lavrnja, Irena and Stojiljković, Mirjana and Rakić, Ljubisav and Nedeljković, Nadežda",
year = "2010",
abstract = "Biochemical properties of nucleotide pyrophosphatase/phosphodiesterase (NPP) in rat serum have been described by assessing its nucleotide phosphodiesterase activity, using p-nitrophenyl-5-thymidine monophosphate (p-Nph-5-TMP) as a substrate. It was demonstrated that NPP activity shares some typical characteristics described for other soluble NPP, such as divalent cation dependence, strong alkaline pH optimum (pH 10.5), inhibition by glycosaminoglycans, and K (m) for p-Nph-5-TMP hydrolysis of 61.8 +/- A 5.2 mu M. In order to characterize the relation between phosphodiesterase and pyrophosphatase activities of NPP, we have analyzed the effects of different natural nucleotides and nucleotide analogs. ATP, ADP, and AMP competitively inhibited p-Nph-5-TMP hydrolysis with K (i) values ranging 13-43 mu M. Nucleotide analogs, alpha,beta-metATP, BzATP, 2-MeSATP, and dialATP behaved as competitive inhibitors, whereas alpha,beta-metADP induced mixed inhibition, with K (i) ranging from 2 to 20 mu M. Chromatographic analysis revealed that alpha,beta-metATP, BzATP, and 2-MeSATP were catalytically degraded in the serum, whereas dialATP and alpha,beta-metADP resisted hydrolysis, implying that the former act as substrates and the latter as true competitive inhibitors of serum NPP activity. Since NPP activity is involved in generation, breakdown, and recycling of extracellular adenine nucleotides in the vascular compartment, the results suggest that both hydrolyzable and non-hydrolyzable nucleotide analogs could alter the amplitude and direction of ATP actions and could have potential therapeutic application.",
journal = "Molecular and Cellular Biochemistry",
title = "Biochemical characterization of soluble nucleotide pyrophosphatase/phosphodiesterase activity in rat serum",
volume = "339",
number = "1-2",
pages = "99-106",
doi = "10.1007/s11010-009-0373-1"
}

Laketa, D., Bjelobaba, I., Savić, J., Lavrnja, I., Stojiljković, M., Rakić, L.,& Nedeljković, N.. (2010). Biochemical characterization of soluble nucleotide pyrophosphatase/phosphodiesterase activity in rat serum. in Molecular and Cellular Biochemistry, 339(1-2), 99-106.
https://doi.org/10.1007/s11010-009-0373-1

Laketa D, Bjelobaba I, Savić J, Lavrnja I, Stojiljković M, Rakić L, Nedeljković N. Biochemical characterization of soluble nucleotide pyrophosphatase/phosphodiesterase activity in rat serum. in Molecular and Cellular Biochemistry. 2010;339(1-2):99-106.
doi:10.1007/s11010-009-0373-1 .

Laketa, Danijela, Bjelobaba, Ivana, Savić, Jasmina, Lavrnja, Irena, Stojiljković, Mirjana, Rakić, Ljubisav, Nedeljković, Nadežda, "Biochemical characterization of soluble nucleotide pyrophosphatase/phosphodiesterase activity in rat serum" in Molecular and Cellular Biochemistry, 339, no. 1-2 (2010):99-106,
https://doi.org/10.1007/s11010-009-0373-1 . .