Browsing by Subject "enzyme activity"

Article

Calpain2 protease: A new member of the Wnt/Ca2+ pathway modulating convergent extension movements in Xenopus

Zanardelli, Sara; Christodoulou, Neophytos; Skourides, Paris A. (2013)

Calpains are a family of calcium-dependent intracellular cysteine proteases that regulate several physiological processes by limited cleavage of different substrates. The role of Calpain2 in embryogenesis is not clear with ...

Article

Commitment to erythroid differentiation in mouse erythroleukemia cells is controlled by alterations in topoisomerase IIα phosphorylation

Constantinou, Andreas I.; Vaughan, A. T. M.; Yamasaki, H.; Kamath, N. (1996)

To explore the program of cell differentiation in Friend murine erythroleukemia (MEL) cells, we used three clonal variants: phorbol 12- myristate 13-acetate (PMA)-hypersensitive TS-19-101, PMA-resistant TR19-9, and ...

Article

Composition and histone substrates of polycomb repressive group complexes change during cellular differentiation

Kuzmichev, A.; Margueron, R.; Vaquero, A.; Preissner, T. S.; Scher, M.; Kirmizis, Antonis; Ouyang, X.; Brockdorff, N.; Abate-Shen, C.; Farnham, P.; Reinberg, D. (2005)

Changes in the substrate specificities of factors that irreversibly modify the histone components of chromatin are expected to have a profound effect on gene expression through epigenetics. Ezh2 is a histone-lysine ...

Article

Detection of the His-heme Fe2+-NO species in the reduction of NO to N2O by ba3-oxidase from thermus thermophilus

Pinakoulaki, Eftychia; Ohta, T.; Soulimane, T.; Kitagawa, T.; Varotsis, Constantinos (2005)

Reaction pathways in the enzymatic formation and cleavage of the N-N and N-O bonds, respectively, are difficult to verify without the structure of the intermediates, but we now have such information on the heme a3 2+-NO ...

Article

Flavonoids as DNA topoisomerase antagonists and poisons: Structure-activity relationships

Constantinou, Andreas I.; Mehta, R.; Runyan, C.; Rao, K.; Vaughan, A.; Moon, R. (1995)

Selected flavonoids were tested for their ability to inhibit the catalytic activity of DNA topoisomerase (topo) I and II. Myricetin, quercetin, fisetin, and morin were found to inhibit both enzymes, while phloretin, ...

Article

Fourier transform infrared (FTIR) and step-scan time-resolved FTIR spectroscopies reveal a unique active site in cytochrome caa3 oxidase from Thermus thermophilus

Pinakoulaki, Eftychia; Soulimane, T.; Varotsis, Constantinos (2002)

Fourier transform infrared (FTIR) and step-scan time-resolved FTIR difference spectra are reported for the [carbonmonoxy]cytochrome caa3 from Thermus thermophilus. A major C-O mode of heme a3 at 1958 cm-1 and two minor ...

Article

Histone H3 tail clipping regulates gene expression

Santos-Rosa, H.; Kirmizis, Antonis; Nelson, C.; Bartke, T.; Saksouk, N.; Cote, J.; Kouzarides, T. (2009)

Induction of gene expression in yeast and human cells involves changes in the histone modifications associated with promoters. Here we identify a histone H3 endopeptidase activity in Saccharomyces cerevisiae that may ...

Article

HIV-1 integrase: From biology to chemotherapeutics

Zeinalipour-Loizidou, E.; Nicolaou, Charalambos P.; Nicolaïdes, Andrew N.; Kostrikis, Leontios G. (2007)

AIDS has claimed the lives of 25 million people worldwide, an additional 40 million people are HIV-infected and new cases are being diagnosed every year. Despite the fact that HAART has moved AIDS from the category of ...

Article

HIV-1 integrase: From biology to chemotherapeuticsAAA

Zeinalipour-Loizidou, E.; Nicolaou, Charalambos P.; Nicolaïdes, Andrew N.; Kostrikis, Leontios G. (2007)

AIDS has claimed the lives of 25 million people worldwide, an additional 40 million people are HIV-infected and new cases are being diagnosed every year. Despite the fact that HAART has moved AIDS from the category of ...

Article

Identification of a series of novel derivatives as potent HCV inhibitors by a ligand-based virtual screening optimized procedure

Melagraki, G.; Afantitis, Antreas; Sarimveis, H.; Koutentis, Panayiotis Andreas; Markopoulos, J.; Igglessi-Markopoulou, O. (2007)

This paper presents the results of a ligand-based virtual screening optimized procedure on 98 compounds which have been recently evaluated as inhibitors of genotype 1 HCV polymerase. First, quantitative structure-activity ...

Article

Imaging morphogenesis, in Xenopus with Quantum Dot nanocrystals

Stylianou, Panayiota; Skourides, Paris A. (2009)

Mesoderm migration is a well studied morphogenetic movement that takes place during Xenopus gastrulation. The study of mesoderm migration and other morphogenetic movements has been primarily based on in vitro assays due ...

Article

Implications of HIV-1 M group polymorphisms on integrase inhibitor efficacy and resistance: Genetic and structural in silico analyses

Loizidou, Eriketi Z.; Kousiappa, Ioanna; Zeinalipour-Yazdi, Constantinos D.; Van De Vijver, D. A. M. C.; Kostrikis, Leontios G. (2009)

The extensive polymorphisms among HIV-1 subtypes have been implicated in drug resistance development. Integrase inhibitors represent the latest addition to the treatment of HIV-1, and their efficacy and resistance patterns ...

Article

Implications of HIV-1 M group polymorphisms on integrase inhibitor efficacy and resistance: Genetic and structural in silico analyses

Loizidou, Eriketi Z.; Kousiappa, Ioanna; Zeinalipour-Yazdi, Constantinos D.; Van De Vijver, D. A. M. C.; Kostrikis, Leontios G. (2009)

The extensive polymorphisms among HIV-1 subtypes have been implicated in drug resistance development. Integrase inhibitors represent the latest addition to the treatment of HIV-1, and their efficacy and resistance patterns ...

Article

Induction of DNA damage and caspase-independent programmed cell death by vitamin e

Constantinou, Constantina; Neophytou, Christiana M.; Vraka, Panayiota S.; Hyatt, John Anthony; Papas, Konstantinos A.; Constantinou, Andreas I. (2012)

Vitamin E comprises 8 functionally unique isoforms and may be a suitable candidate for the adjuvant treatment of prostate cancer. In this study, we examined the ability of 2 vitamin E isoforms [α-tocotrienol (γ-TT) and ...

Article

Inhibition of N-methyl-N-nitrosourea-induced mammary tumors in rats by the soybean isoflavones

Constantinou, Andreas I.; Mehta, R. G.; Vaughan, A. (1996)

Soy-based diets, rich in the isoflavones genistein and daidzein, are thought to protect against breast and prostate cancer. Soy-based diets, rich in the isoflavones genistein and daidzein, are thought to protect against ...

Article

Inhibition of topoisomerase IIα activity in CHO K1 cells by 2- [(aminopropyl)amino]ethanethiol (WR-1065)

Grdina, D. J.; Constantinou, Andreas I.; Shigematsu, N.; Murley, J. S. (1994)

The aminothiol 2-[(aminopropyl)amino]ethanethiol (WR-1065) is the active thiol of the clinically studied radioprotective agent S-2-(3- aminopropylamino)ethylphosphorothioic acid (WR-2721). WR-1065 is an effective radiation ...

Article

N-alpha-terminal Acetylation of Histone H4 Regulates Arginine Methylation and Ribosomal DNA Silencing

Schiza, V.; Molina-Serrano, D.; Kyriakou, DImitris; Hadjiantoniou, A.; Kirmizis, Antonis (2013)

Post-translational modifications of histones play a key role in DNA-based processes, like transcription, by modulating chromatin structure. N-terminal acetylation is unique among the numerous histone modifications because ...

Article

A novel use for the comet assay: Detection of topoisomerase II inhibitors

Salti, G. I.; Das Gupta, T. K.; Constantinou, Andreas I. (2000)

Background: The simple and quick comet assay can quantitatively detect DNA cleavage in cells. This study aimed to determine whether the comet assay could be used to detect topoisomerase (topo) II inhibitors. Materials and ...

Article

Novobiocin- and Phorbol-12-myristate-13-acetate-induced Differentiation of Human Leukemia Cells Associated with a Reduction in Topoisomerase II Activity

Constantinou, Andreas I.; Henning-Chubb, C.; Huberman, E. (1989)

Studies were conducted to determine the possible involvement of DNA topoisomerase II (Topo II) in the induction of differentiation in two human promyelocytic HL-60 leukemia cell variants that are either susceptible or ...

Article

The origin of the Fe IV = O intermediates in cytochrome aa 3 oxidase

Pinakoulaki, Eftychia; Daskalakis, Vangelis; Varotsis, Constantinos (2012)

The dioxygen reduction mechanism in cytochrome oxidases relies on proton control of the electron transfer events that drive the process. Proton delivery and proton channels in the protein that are relevant to substrate ...