Alzheimer's Peptide Aβ1-42, an amyoid beta peptide, is found in plaques in the brains of Alzheimer's disease patients, and accumulation of this very hydrophobic peptide is thought to be the direct cause of the disease. However, the reason for accumulation is not clear. A common theory is that the balance between production and degradation of this peptide is disrupted in the disease. One method whereby degradation of the peptide can be inhibited is by modification into a form which is resistant to enzymatic degradation (proteolysis). In peptides, isomerization of aspartic acid into isoaspartic acid (where the peptide bond is via the side-chain beta carbon rather than the normal backbone alpha carbon) is known to inhibit enzymatic degradation, and may be the elusive Alzheimer's "trigger", which results in decreased degradation and therefore accumulation of the peptide. Nadia Sargaeva of Prof.  Peter O'Connor's group has developed a new mass spectrometric method for detecting this isomerization and tested it out on the worst variant of the amyloid beta peptide, the full length version containing amino acids 1-42. 

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Ioana Dumitrescu, Patrick R. Unwin and Julie V. Macpherson make the cover of Chem.Commun with their feature article on Electrochemistry at carbon nanotubes (CNTs): It is a large and growing field, but one in which there is still uncertainty about the fundamental activity of CNTs as electrode materials. On the one hand, there are many reports which focus on the favourable electrochemical properties of CNT electrodes, such as enhanced detection sensitivity, electrocatalytic effects and reduced fouling. On the other hand, other studies suggest that CNTs may be no more electroactive than graphitic powder. Furthermore, it has been proposed that the catalytic nanoparticles from which CNTs are formed may dominate the electrochemical characteristics in some instances. A considerable body of the literature presumes that the CNT sidewall is inert and that edge-plane-graphite-like open ends and defect sites are responsible for the electron transfer activity observed. In contrast, studies of well characterised single-walled nanotube (SWNT) electrodes, either as individual tubes or as two-dimensional networks, suggest sidewall activity. This review highlights how the various discrepancies in CNT electrochemistry may have arisen, by taking a historical view of the field and identifying crucial issues that still need to be solved. When assessing the behaviour of CNT electrodes, it is vitally important that careful consideration is given to the type of CNT used (SWNT or multi-walled), the quality of the material (presence of impurities), the effect of chemical processing steps in the fabrication of electrodes and the experimental arrangements adopted. Understanding these key features is an essential requirement to develop a fundamental understanding of CNT electrochemistry, to allow a wide range of electroanalytical applications, and to move the field forward rationally. As part of this process, high resolution electrochemical and electrical imaging techniques are expected to play a significant role in the future, as well as theoretical developments which examine the fundamentals of electron transfer at different types of CNTs and their characteristic surface sites. http://dx.doi.org/10.1039/b909734a