Protonation reactions of Glyn homologues were studied in order to elucidate the effect of peptide chain length and matrix materials on the matrix-assisted laser desorption ionization (MALDI) mechanism. At 337 nm nitrogen laser excitation the relative ion yield-chain length relationship showed considerable variability in 3,5-dimethoxy-4-hydroxycinnamic acid (SA), 2,5-dihydroxybenzoic acid (DHB),...

Product ion yields in postsource decay and photodissociation at 193 and 266 nm were measured for some peptide ions without a basic amino acid residue ([Y(6) + H](+), [F(5) + H](+), and [YPFVEPI + H](+)) generated by matrix-assisted laser desorption ionization (MALDI). Data indicated statistical nature for the dissociation processes. Assuming that peptide ions formed by MALDI are in thermal equi...

Pepper (Capsicum annuum) serotonin N-hydroxycinnamoyltransferase (SHT) catalyzes the synthesis of N-hydroxycinnamic acid amides of serotonin, including feruloylserotonin and p-coumaroylserotonin. To elucidate the domain or the key amino acid that determines the amine substrate specificity, we isolated a tyramine N-hydroxycinnamoyltransferase (THT) gene from pepper. Purified recombinant THT prot...

This study aimed to explore the capability of potentially probiotic bifidobacteria to hydrolyze chlorogenic acid into caffeic acid (CA), and to recognize the enzymes involved in this reaction. Bifidobacterium strains belonging to eight species occurring in the human gut were screened. The hydrolysis seemed peculiar of Bifidobacterium animalis, whereas the other species failed to release CA. Int...

INTRODUCTION Brassica vegetables have been related to the prevention of cancer and degenerative diseases, owing to their glucosinolate and phenolic content. OBJECTIVE Identification of glucosinolates, flavonoids and hydroxycinnamic acids in representative varieties of kale, cabbage and leaf rape. METHODOLOGY One local variety of each crop was evaluated in this study using a multi-purpose ch...

A novel thermotropic liquid crystalline polymers poly{3-benzylidene amino-4-hydroxybenzoic acid (3,4-BAHBA)-co-trans-4-hydroxycinnamic acid (4HCA: trans-coumaric acid)} (Poly(3,4-BAHBA-co-4HCA)), was synthesized by the thermal polycondensation of 4HCA and 3,4-BAHBA, which was synthesized by a reaction of 3-amino-4-hydroxybenzoic acid (3,4-AHBA) with benzaldehyde. When the 4HCA compositions of P...

Polyphenolic profiles in the berry samples of 344 European grape (Vitis vinifera) cultivars were evaluated for two consecutive years. These cultivars represent a diverse collection of V. vinifera germplasm maintained at the USDA-Agricultural Research Service Vitis Clonal Repository in Davis of California, USA. A total of 36 polyphenolic compounds, including 16 anthocyanins, 6 flavonols, 6 flava...

To provide an objective measure of the correlation between the internal energy content of ions generated by matrix-assisted laser desorption/ionization (MALDI) and the matrix properties, a series of well-characterized benzyl-substituted benzylpyridinium salts were used as thermometer molecules (TMs). To determine the internal energy variations of analyte ions, the survival yields of TM molecula...