Belfast Metropolitan College

Belfast, United Kingdom

Belfast Metropolitan College

Belfast, United Kingdom
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McPherson P.A.C.,Belfast Metropolitan College | Bole A.,Belfast Metropolitan College | Bole A.,Queen's University of Belfast | Cruz K.A.,Belfast Metropolitan College | And 3 more authors.
Chemistry and Physics of Lipids | Year: 2012

Lipid peroxidation is a common feature of many chemical and biological processes, and is governed by a complex kinetic scheme. A fundamental stage in kinetic investigations of lipid peroxidation is the accurate determination of the rate of peroxidation, which in many instances is heavily reliant on the method of finite differences. Such numerical approximations of the first derivative are commonly employed in commercially available software, despite suffering from considerable inaccuracy due to rounding and truncation errors. As a simple solution to this, we applied three empirical sigmoid functions (viz. the Prout-Tompkins, Richards & Gompertz functions) to data obtained from the AAPH-mediated peroxidation of aqueous linoleate liposomes in the presence of increasing concentrations of Trolox, evaluating the curve fitting parameters using the widely available Microsoft Excel Solver add-in. We have demonstrated that the five-parameter Richards' function provides an excellent model for this peroxidation, and when applied to the determination of fundamental rate constants, produces results in keeping with those available in the literature. Overall, we present a series of equations, derived from the Richards' function, which enables direct evaluation of the kinetic measures of peroxidation. This procedure has applicability not only to investigations of lipid peroxidation, but to any system exhibiting sigmoid kinetics. © 2012 Elsevier Ireland Ltd.


Atcheson E.,Queen's University of Belfast | Hamilton E.,Queen's University of Belfast | Hamilton E.,Belfast Metropolitan College | Pathmanathan S.,Queen's University of Belfast | And 4 more authors.
Bioscience Reports | Year: 2011

The IQGAP [IQ-motif-containing GAP (GTPase-activating protein)] family members are eukaryotic proteins that act at the interface between cellular signalling and the cytoskeleton. As such they collect numerous inputs from a variety of signalling pathways. A key binding partner is the calcium-sensing protein CaM (calmodulin). This protein binds mainly through a series of IQ-motifs which are located towards the middle of the primary sequence of the IQGAPs. In some IQGAPs, these motifs also provide binding sites for CaM-like proteins such as myosin essential light chain and S100B. Using synthetic peptides and native gel electrophoresis, the binding properties of the IQ-motifs from human IQGAP2 and IQGAP3 have been mapped. The second and third IQ-motifs in IQGAP2 and all four of the IQ-motifs of IQGAP3 interacted with CaM in the presence of calcium ions. However, there were differences in the type of interaction: while some IQ-motifs were able to form complexes with CaM which were stable under the conditions of the experiment, others formed more transient interactions. The first IQ-motifs from IQGAP2 and IQGAP3 formed transient interactions with CaM in the absence of calcium and the first motif from IQGAP3 formed a transient interaction with the myosin essential light chain Mlc1sa. None of these IQ-motifs interacted with S100B. Molecular modelling suggested that all of the IQ-motifs, except the first one from IQGAP2 formed α-helices in solution. These results extend our knowledge of the selectivity of IQ-motifs for CaM and related proteins. ©The Authors Journal compilation ©2011 Biochemical Society.


Andrews W.J.,Queen's University of Belfast | Bradley C.A.,Queen's University of Belfast | Hamilton E.,Queen's University of Belfast | Hamilton E.,Belfast Metropolitan College | And 3 more authors.
Molecular and Cellular Biochemistry | Year: 2012

IQGAPs are cytoskeletal scaffolding proteins which collect information from a variety of signalling pathways and pass it on to the microfilaments and microtubules. There is a well-characterised interaction between IQGAP and calmodulin through a series of IQ-motifs towards the middle of the primary sequence. However, it has been shown previously that the calponin homology domain (CHD), located at the N-terminus of the protein, can also interact weakly with calmodulin. Using a recombinant fragment of human IQGAP1 which encompasses the CHD, we have demonstrated that the CHD undergoes a calcium ion-dependent interaction with calmodulin. The CHD can also displace the hydrophobic fluorescent probe 1-anilinonaphthalene-8-sulphonate from calcium-calmodulin, suggesting that the interaction involves non-polar residues on the surface of calmodulin. Molecular modelling identified a possible site on the CHD for calmodulin interaction. The physiological significance of this interaction remains to be discovered. © 2012 Springer Science+Business Media, LLC.


McPherson P.A.C.,Belfast Metropolitan College | Boyle P.M.,Belfast Metropolitan College | Boyle P.M.,Liverpool John Moores University | Turemen B.T.,Belfast Metropolitan College
Biochemical and Biophysical Research Communications | Year: 2013

Nanosized titanium dioxide (TiO2) is a common component of sunscreen preparations and cosmetics as it reflects UV and visible light in accordance to Rayleigh's law. However, in aqueous environments, TiO2 is an efficient photocatalyst, producing superoxide (O2-) and hydroxyl (HO) radicals, which are highly damaging to biomolecules. We investigated the role of TiO2 in promoting the peroxidation of linoleic acid (LA) alone and in the presence of hypochlorous acid (HOCl). TiO2 significantly enhanced peroxidation of LA, which was further enhanced in the presence of HOCl. This latter finding involved the formation of singlet molecular oxygen in a Russell-type mechanism appearing to involve preformed lipid hydroperoxides (LOOH). In addition to lipid peroxidation, HOCl also mediated formation of 18:1 monochlorohydrins, which in the presence of TiO2 appeared to decompose to kinetic products which supplemented peroxidation of linoleic acid. We present a theoretical mechanism which fits the available experimental data and may partially explain the dichotomy associated with HOCls role in lipid modification. © 2012 Elsevier Inc.


McPherson P.A.C.,Belfast Metropolitan College | Turemen B.T.,Belfast Metropolitan College
Biochemical and Biophysical Research Communications | Year: 2014

Oxidized protein adducts are formed under conditions of oxidative stress and may represent a valuable biomarker for a variety of diseases which share this common aetiology. A suitable candidate biomarker for oxidized proteins is protein-bound 3,4-dihydroxyl-l-phenylalanine (l-DOPA), which is formed on 3′-hydroxylation of tyrosine residues by hydroxyl radicals. Existing methodologies to measure protein-bound l-DOPA employ lengthy acid hydrolysis steps (ca. 16 h) which may cause artifactual protein oxidation, followed by HPLC with detection based on the intrinsic fluorescence of l-DOPA. We report a novel method for the measurement of protein-bound l-DOPA which involves rapid hydrolysis followed by pre-column concentration of 6-aminoquinolyl-derivatives using cloud-point extraction. The derivatized material is resolved by reversed-phase HPLC in less than 30 min and has derivatization chemistry compatible with both UV and fluorescent detection, providing detection down to the femtomole level. The method provides identical results to those found with highly specific ELISA-based techniques and requires only basic instrumentation. The stability of the 6-aminoquinolyl-derivatives together with the fast and sensitive nature of the assay will be appealing to those who require large sample throughput. © 2014 Elsevier Inc. All rights reserved.


PubMed | Belfast Metropolitan College
Type: Journal Article | Journal: Journal of physiology and biochemistry | Year: 2012

Ketogenesis is the branch of mammalian metabolism concerned with the synthesis of ketone bodies. In this process, the small, water-soluble compounds acetoacetate, D-3--hydroxybutyrate and propanone are produced by the liver in response to reduced glucose availability. Although ketone bodies are always present at a low level in healthy individuals, dietary manipulation and certain pathological conditions can increase the levels of these compounds in vivo. In some instances, such as in refractory epilepsy, high levels of ketone bodies can be beneficial-in this instance, by exerting an anticonvulsant effect. Conversely, if the levels of ketones rise to supraphysiological levels, as can occur in diabetes mellitus, a state of ketoacidosis can occur, which has serious consequences for cellular function. More recently, research has identified a possible link between ketogenesis and free radical-mediated pathologies, highlighting the potential application of ketogenic diets to the treatment of conditions such as Alzheimers disease. Overall, an understanding of ketone body metabolism and its links to human disease may prove to be vital in developing new regimens for the treatment of human disease.


PubMed | Belfast Metropolitan College
Type: Journal Article | Journal: Mini reviews in medicinal chemistry | Year: 2012

It has long been recognised that high circulating levels of cholesterol are associated with the development of cardiovascular disease. With the discovery of the cholesterol biosynthetic pathway in 1950, it was soon realised that blockade of key conversions in this pathway may provide useful therapeutic targets for the management of hypercholesterolaemia. In the 1970s the first useful inhibitors of cholesterol biosynthesis were isolated, and paved the way for what would become a multimillion dollar pharmaceutical industry. Modern-day statins are incredibly effective hypolipidaemic agents, interrupting cholesterol biosynthesis at the rate-limiting step through a competitive inhibition mechanism. These compounds structures interact with key amino acid residues through a variety of defined bonding interactions, and by understanding how these interactions form, better, and safer, hypolipidaemic agents were found. This review describes the historical development of statins and brings us up-to-date with current structure-activity relationships between statins and their target enzyme.


PubMed | Belfast Metropolitan College
Type: Journal Article | Journal: Biochemical and biophysical research communications | Year: 2014

Oxidized protein adducts are formed under conditions of oxidative stress and may represent a valuable biomarker for a variety of diseases which share this common aetiology. A suitable candidate biomarker for oxidized proteins is protein-bound 3,4-dihydroxyl-l-phenylalanine (l-DOPA), which is formed on 3-hydroxylation of tyrosine residues by hydroxyl radicals. Existing methodologies to measure protein-bound l-DOPA employ lengthy acid hydrolysis steps (ca. 16h) which may cause artifactual protein oxidation, followed by HPLC with detection based on the intrinsic fluorescence of l-DOPA. We report a novel method for the measurement of protein-bound l-DOPA which involves rapid hydrolysis followed by pre-column concentration of 6-aminoquinolyl-derivatives using cloud-point extraction. The derivatized material is resolved by reversed-phase HPLC in less than 30min and has derivatization chemistry compatible with both UV and fluorescent detection, providing detection down to the femtomole level. The method provides identical results to those found with highly specific ELISA-based techniques and requires only basic instrumentation. The stability of the 6-aminoquinolyl-derivatives together with the fast and sensitive nature of the assay will be appealing to those who require large sample throughput.


Grant
Agency: GTR | Branch: Innovate UK | Program: | Phase: Knowledge Transfer Partnership | Award Amount: 145.20K | Year: 2015

To design and manufacture a new product range from advanced materials to improve competitiveness in global markets for bulk materials conveyance systems and to improve processes to improve cost and time efficiency and reduce waste.


Grant
Agency: GTR | Branch: Innovate UK | Program: | Phase: Knowledge Transfer Partnership | Award Amount: 72.60K | Year: 2011

To realign the internal functions in order to facilitate the exploitation of product and market opportunities presenting in the financial services sector.

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