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Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Variability Of Placental Expression Of Cyclin E Low Molecular Weight Variants, A Bukovsky, Maria Cekanova, Mr Caudle, J Wimalasena, Js Foster, Ja Keenan, Rf Elder Jul 2002

Variability Of Placental Expression Of Cyclin E Low Molecular Weight Variants, A Bukovsky, Maria Cekanova, Mr Caudle, J Wimalasena, Js Foster, Ja Keenan, Rf Elder

Maria Cekanova MS, RNDr, PhD

Cyclin E, a G(1) cyclin serving to activate cyclin-dependent kinase 2, is the only cyclin gene for which alternative splicing leading to structurally different proteins has been described. Different cyclin E proteins are present in tumor tissues but absent from normal (steady) tissues. Cyclin E contributes to the regulation of cell proliferation and ongoing differentiation and aging. Because trophoblast has invasive properties and differentiates into syncytium and placental aging may develop at term, we examined cyclin E protein variants in human placenta. Placental samples were collected from 27 deliveries between 33 and 41 wk and were compared with ovarian ...


Effect Of Acetazolamide On Hypericin Photocytotoxicity, P Solar, I Cavarga, J Hofmanova, Maria Cekanova, P Miskovsky, P Brezani, G Hrckova, A Kozubik, P Fedorocko Jun 2002

Effect Of Acetazolamide On Hypericin Photocytotoxicity, P Solar, I Cavarga, J Hofmanova, Maria Cekanova, P Miskovsky, P Brezani, G Hrckova, A Kozubik, P Fedorocko

Maria Cekanova MS, RNDr, PhD

The photodynamic action of hypericin (HYP) in vitro was evaluated using human leukemic HL-60 and lung carcinoma A549 cell lines. After illumination HYP (1 x 10 (-5) M) reduced the proliferation and/or survival of HL-60 and A549 cells vs. controls to almost to 0 % and 29 %, respectively. A lower concentration of HYP (1 x 10 (-6) M) decreased the proliferation and/or survival only in HL-60 cells. Non-cytotoxic concentrations of the carbonic anhydrase inhibitor acetazolamide (ACTZ) (1 x 10 (-3)-1 x 10 (-6) M) significantly potentiated these effects of HYP (1 x 10 (-6)M) in HL-60, but ...


Mechanism Of Abietadiene Synthase Catalysis: Stereochemistry And Stabilization Of The Cryptic Pimarenyl Carbocation Intermediates, Reuben J. Peters, Matthew M. Ravn, Robert M. Coates, Rodney Croteau Jun 2002

Mechanism Of Abietadiene Synthase Catalysis: Stereochemistry And Stabilization Of The Cryptic Pimarenyl Carbocation Intermediates, Reuben J. Peters, Matthew M. Ravn, Robert M. Coates, Rodney Croteau

Reuben J. Peters

Abietadiene synthase (AS) catalyzes the complex cyclization-rearrangement of (E,E,E)-geranylgeranyl diphosphate (8, GGPP) to a mixture of abietadiene (1a), double bond isomers 2a-4a and pimaradienes 5a-7a as a key step in the biosynthesis of the abietane resin acid constituents (1b-4b) of conifer oleoresin. The reaction proceeds at two active sites by way of the intermediate, copalyl diphosphate (9). In the second site, a putative tricyclic pimaradiene or pimarenyl(+) carbocation intermediate of undefined C13 stereochemistry and annular double bond position is formed. Three 8-oxy-17-nor analogues of 9 (17 and 19a,b) and three isomeric 15,16-bisnorpimarenyl-N-methylamines (26a-c) were synthesized ...


Abietadiene Synthase Catalysis:  Conserved Residues Involved In Protonation-Initiated Cyclization Of Geranylgeranyl Diphosphate To (+)-Copalyl Diphosphate, Reuben J. Peters, Rodney B. Croteau Feb 2002

Abietadiene Synthase Catalysis:  Conserved Residues Involved In Protonation-Initiated Cyclization Of Geranylgeranyl Diphosphate To (+)-Copalyl Diphosphate, Reuben J. Peters, Rodney B. Croteau

Reuben J. Peters

Abietadiene synthase catalyzes two sequential, mechanistically distinct cyclization reactions in the formation of a mixture of abietadiene double bond isomers as the committed step in resin acid biosynthesis. Each reaction is carried out at a separate active site residing in a structurally distinct domain, and the reactions are kinetically separable. The first cyclization reaction is initiated by protonation of the terminal double bond of the universal diterpene precursor, geranylgeranyl diphosphate. The pH dependence of the overall reaction is consistent with an acid-base catalytic mechanism, and a divalent metal ion plays a role in this reaction probably by binding the diphosphate ...


Variability Of Placental Expression Of Cyclin E Low Molecular Weight Variants, A Bukovsky, Maria Cekanova Ms, Rndr, Phd, Mr Caudle, J Wimalasena, Js Foster, Ja Keenan, Rf Elder Jan 2002

Variability Of Placental Expression Of Cyclin E Low Molecular Weight Variants, A Bukovsky, Maria Cekanova Ms, Rndr, Phd, Mr Caudle, J Wimalasena, Js Foster, Ja Keenan, Rf Elder

Faculty Publications and Other Works -- Biochemistry, Cellular and Molecular Biology

No abstract provided.


Variability Of Placental Expression Of Cyclin E Low Molecular Weight Variants, A Bukovsky, Maria Cekanova Ms, Rndr, Phd, Mr Caudle, J Wimalasena, Js Foster, Ja Keenan, Rf Elder Dec 2001

Variability Of Placental Expression Of Cyclin E Low Molecular Weight Variants, A Bukovsky, Maria Cekanova Ms, Rndr, Phd, Mr Caudle, J Wimalasena, Js Foster, Ja Keenan, Rf Elder

Maria Cekanova MS, RNDr, PhD

No abstract provided.