Determination of the specific heat using laser flash apparatus

Journal of Thermal Analysis and Calorimetry - The main aim of this article was to describe the methodology for the measurement of specific heat using the laser flash apparatus. The obtained values...     

Structure and Mechanism of an Aspartimide‐Dependent Peptide Ligase in Human Legumain

Peptide ligases expand the repertoire of genetically encoded protein architectures by synthesizing new peptide bonds, energetically driven by ATP or NTPs. Here, we report the discovery of a genuine ligase activity in human legumain (AEP) which has important roles in immunity and tumor progression that were believed to be due to its established cysteine protease activity. Defying dogma, the ligase reaction is independent of the catalytic cysteine but exploits an endogenous energy reservoir that results from the conversion of a conserved aspartate to a metastable aspartimide. Legumain’s dual protease–ligase activities are pH‐ and thus localization controlled, dominating at acidic and neutral pH, respectively. Their relevance includes reversible on–off switching of cystatin inhibitors and enzyme (in)activation, and may affect the generation of three‐dimensional MHC epitopes. The aspartate–aspartimide (succinimide) pair represents a new paradigm of coupling endergonic reactions in ATP‐scarce environments.     

Hydrogenations at Room Temperature and Atmospheric Pressure with Mesoionic Carbene‐Stabilized Borenium Catalysts

1,2,3‐Triazolylidene‐based mesoionic carbene boranes have been synthesized in a convenient one‐pot protocol from the corresponding 1,2,3‐triazolium salts, base, and borane. Borenium ions are obtained by hydride abstraction and serve as catalysts in mild hydrogenation reactions of imines and unsaturated N‐heterocycles at ambient pressure and temperature.     

Design of phosphonate analogs of short peptides by “click” chemistry

Methods were developed for the first time for the modification of the natural neuropeptides Ile–Gly–Leu and Leu–Gly–Leu simultaneously with the phosphonate moiety and the triazole ring or solely with the triazole ring by means of click chemistry. All of the peptidomimetics synthesized were isolated as a mixture of diastereomers and were characterized by spectroscopic methods.

     

Diphenyl[(3,5-di-tert-butyl-4-oxo-2,5-cyclohexadienylidene)-methyl]phosphonate in reactions with o-phenylenediamine

Russian Journal of General Chemistry -     

Interaction of amorphous and crystalline nickel nanoparticles with hydrogen

Nickel nanoparticles were deposited on the surface of highly oriented pyrolytical graphite by laser electrodispersion and precipitation from a solution of reverse micelles. The particles were studied using scanning tunneling microscopy and spectroscopy as well as Auger spectroscopy. The elemental composition of the nanoparticles and specific features of the electronic structure of their surface were determined. Adsorption of molecular hydrogen was also studied.