Pyruvoyl, a novel amino protecting group on the solid phase peptide synthesis and the peptide condensation reaction

Novel α-Oxoamide Advanced-Glycation Endproducts within the N6-Carboxymethyl Lysine and N6-Carboxyethyl Lysine Reaction Cascades

The highly reactive α-dicarbonyl compounds glyoxal and methylglyoxal are major precursors of posttranslational protein modifications in vivo. Model incubations of N²-t-Boc-lysine and either glyoxal or methylglyoxal were used to further elucidate the underlying mechanisms of the N⁶-carboxymethyl lysine and N⁶-carboxyethyl lysine reaction cascades. After independent synthesis of the authentic reference standards, we were able to detect N⁶-glyoxylyl lysine and N⁶-pyruvoyl lysine for the first time by HPLC-MS² analyses. These two novel amide advanced-glycation endproducts were exclusively formed under aerated conditions, suggesting that they were potent markers for oxidative stress. Analogous to the well-known Strecker degradation pathway, leading from amino acids to Strecker acids, the oxidation of an enaminol intermediate is suggested to be the key mechanistic step. A highly sensitive workup for the determination of AGEs in tissues was developed. In support of our hypothesis, the levels of N⁶-glyoxylyl lysine and N⁶-pyruvoyl lysine in rat livers indeed correlated with liver cirrhosis and aging.

An Efficient Synthesis of Milnacipran Hydrochloride via Reductive Amination of Aldehyde

An efficient synthesis of milnacipran hydrochloride has been accomplished. The important application of this paper is the reductive amination of aldehyde to primary amine with water soluble reagents. This method provides a high yield of primary amine as the major product, reduces the number of steps, and discourages by-products.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: an update for 2009-2010

This review is the sixth update of the original article published in 1999 on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2010. General aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, arrays and fragmentation are covered in the first part of the review and applications to various structural typed constitutes the remainder. The main groups of compound that are discussed in this section are oligo and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Many of these applications are presented in tabular form. Also discussed are medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis.