In these reports the separation were obtained by using specimens or deionized sample of NeuAc-containing compounds and the resolution was attained with acidic diluted phosphate or acetate buffer.We chose serotonin-immobilized silica as solid phase extraction (SPE) particles for NeuAc-containing glycoconjugates, 2010 © The Japan Society for Analytical Chemistry † To whom correspondence should be addressed. E-mail: suzuki@phar.kindai.ac.jp specific Extraction of sialic-acid-containing Glycans and Glycopeptides using serotonin-bonded silica Masahiro Yodoshi, tomoko ikuta, Yukie Mouri, and shigeo suzuki † Department of Pharmaceutical Sciences, Kinki University, Japan Serotonin-bonded silica was developed for specific extraction of sialic-acid-containing glycans and glycopeptides. Serotonin, coupled by reductive amination with aldehyde silica particles via its ethylamino group, has strong affinity to sialic acid in glycan chain termini. Sialylated glycans trapped on serotonin silica particles are released by washing with ammonium acetate solution, providing highly efficient specific trap and release glycoconjugates. With >100 μmol/g adsorption capacity, the particles are applicable to purify labeled glycans after derivatization with 2-aminopyridine to remove excess reagents. Serotonin silica efficiently enriches sialic-acid-containing glycopeptides from tryptic digests for LC/MS analysis of glycans' heterogeneity in glycoproteins.

Enzyme models are of practical importance for the development of efficient molecular catalysts for organic reactions and of theoretical importance in elucidating mechanisms of enzymatic reactions.[1] In comparison with hydrolase models, an artificial acyltransferase that promotes the reverse reaction of dehydrocondensation is particularly difficult to design.[2]As a representative host compound, [18]crown-6 has received much attention in biomimetic chemistry and, although specific binding of ammonium ions to [18]crown-6 has been extensively investigated, [3][4][5] application of the complex as an artificial acyltransferase is very limited. [6,7] Among acyltransferase models, cyclotransferase models that catalyze intramolecular dehydrocondensation to lead to the formation of lactams have not been developed. Herein, we report a novel enzyme model of cyclotransferase, [8] which utilizes the specific binding of a primary ammonium ion and [18]crown-6. The artificial enzyme substrate specifically activates the carboxylic acids that possess a primary amino group at the g-, d-, or e-positions, thus leading to the formation of the corresponding lactams.The reaction system is outlined in Scheme 1. Methanol is employed as the solvent as it dissolves the amino acid substrates and stabilizes the complex of the primary ammonium salt and the [18]crown-6. [9][10][11] A combination system of triazines and tertiary amines which is available in alcohols was attached to the [18]crown-6 and employed for the activation of the substrate carboxyl groups. [12,13] When CDMT was added to a methanolic solution of 5-aminovaleric acid (3 a) and crown derivative 1, which can be compared to an apoenzyme,[*] Prof.

Enzyme models are of practical importance for the development of efficient molecular catalysts for organic reactions and of theoretical importance in elucidating mechanisms of enzymatic reactions.[1] In comparison with hydrolase models, an artificial acyltransferase that promotes the reverse reaction of dehydrocondensation is particularly difficult to design.[2]As a representative host compound, [18]crown-6 has received much attention in biomimetic chemistry and, although specific binding of ammonium ions to [18]crown-6 has been extensively investigated, [3][4][5] application of the complex as an artificial acyltransferase is very limited. [6,7] Among acyltransferase models, cyclotransferase models that catalyze intramolecular dehydrocondensation to lead to the formation of lactams have not been developed. Herein, we report a novel enzyme model of cyclotransferase, [8] which utilizes the specific binding of a primary ammonium ion and [18]crown-6. The artificial enzyme substrate specifically activates the carboxylic acids that possess a primary amino group at the g-, d-, or e-positions, thus leading to the formation of the corresponding lactams.The reaction system is outlined in Scheme 1. Methanol is employed as the solvent as it dissolves the amino acid substrates and stabilizes the complex of the primary ammonium salt and the [18]crown-6. [9][10][11] A combination system of triazines and tertiary amines which is available in alcohols was attached to the [18]crown-6 and employed for the activation of the substrate carboxyl groups. [12,13] When CDMT was added to a methanolic solution of 5-aminovaleric acid (3 a) and crown derivative 1, which can be compared to an apoenzyme,[*] Prof.