Such studies have shown that the scattering is from a single atom of the scattering sample. For an electron beam with a well defined incident energy, the scattered electron energy at any angle from each atomic species is Doppler broadened. The broadening reflects the atomic momentum distribution contributed by both the internal and external motions of the molecular system. By measuring the Doppler broadening
of the scattered electron lines it was possible to determine the kinetic energy of the scattering atom including that of its zero-point motion. Thus, the atomic kinetic energies in gases such as H-2, D-2, HD, CH4 and in H2O, D2O and NH3 were measured and compared with those calculated semi-empirically using the measured optical infra red (IR) Cediranib and Raman frequencies of the internal vibrations of the molecules. In general, good agreement between the measured and calculated values was found. Electron scattering was also used to study the ratio of e-scattering intensities from the H- and O-atoms in water (H2O), where some anomalies were reported to exist. (C) 2014 Elsevier B.V. All rights reserved.”
“Protein acetylation is a widespread modification that is mediated by site-selective acetyltransferases. KATs (lysine N-epsilon-acetyltransferases), modify the side chain of specific Cyclosporin A lysines on histones and other proteins, a central process
in regulating gene expression. N-alpha-terminal
acetylation occurs on the ribosome where the alpha amino group of nascent polypeptides is acetylated by NATs(N-terminal acetyltransferase). In yeast, three different NAT complexes were identified NatA, NatB, and NatC. NatA is composed of two main subunits, the catalytic subunit Naa10p (Ard1p) and Naa15p (Nat1p). Naa50p (Nat5) is physically associated with NatA. In man, hNaa50p was shown to have acetyltransferase activity and to be important for chromosome segregation. In this study, we used purified recombinant hNaa50p and multiple oligopeptide substrates to identify and characterize an N-alpha-acetyltransferase activity of hNaa50p. As the preferred substrate this activity 5-Fluoracil acetylates oligopeptides with N termini Met-Leu-Xxx-Pro. Furthermore, hNaa50p autoacetylates lysines 34, 37, and 140 in vitro, modulating hNaa50p substrate specificity. In addition, histone 4 was detected as a hNaa50p KAT substrate in vitro. Our findings thus provide the first experimental evidence of an enzyme having both KAT and NAT activities.”
“Catalysis of Cope-type rearrangements of bis-homoallylic hydroxylamines is demonstrated using chiral thiourea derivatives. This formal intramolecular hydroamination reaction provides access to highly enantioenriched alpha-substituted pyrrolidine products and represents a complementary approach to metal-catalyzed methods.