The preparation of peptide thioesters using Fmoc chemistry requires their synthesis as amides flowed by an N -> S-acyl shift reaction. Recently, bis(2-sulfanylethyl)amino-trityl-polystyrene (SEA) resin has been reported (1, 2), where the peptide is synthesized as a secondary amide, and the N -> S-acyl shift occurs by reaction of one of the two 2-sulfanylethyl groups. The PAET resin described he...

BACKGROUND Oligonucleotide-peptide conjugates have several applications, including their potential use as therapeutic agents. We developed a strategy for the chemical ligation of unprotected peptides to oligonucleotides in aqueous solution. The two compounds are joined via a stable amide bond in a template-directed reaction. RESULTS Peptides, ending in a carboxy-terminal thioester, were conve...

PURPOSE To investigate the effect of the peptide NC-1059 on riboflavin (RF) diffusion across an intact corneal epithelium into the stroma. METHODS NC-1059 peptide was synthesized by solid-phase synthesis with 9-fluorenylmethoxycarbonyl chemistry, characterized by reversed-phase HPLC, and matrix-assisted laser desorption ionization time-of-flight mass spectroscopy. The diffusion of RF across e...

The primary step of the near UV photophysics of a phenylalanine residue is investigated in one- and two-color pump-probe R2PI nanosecond experiments carried out on specific conformers of the Ac-Gly-Phe-NH2 molecule and related neutral compounds isolated in a supersonic expansion. Compared to toluene, whose ππ* state photophysics is dominated by intersystem crossing with a lifetime of ∼80 ns at ...

OBJECTIVE Protease-activated receptors (PARs) 1 and 2 are expressed in various blood vessels including rat aorta, modulating vascular tone. We investigated the roles of PAR-1 and PAR-2 in vasomotor modulation in rat superior mesenteric artery. METHODS AND RESULTS Effects of the PAR-2-activating peptide Ser-Leu-Ile-Gly-Arg-Leu-amide (SLIGRL-amide) and the PAR-1-activating peptide Thr-Phe-Leu-L...

The linear IR and two-dimensional (2D) IR spectra of the amide-I modes of the 12-residue beta-hairpin peptide tryptophan zipper-2 (SWTWENGKWTWK) and its two 13C isotopomers were simulated, with local mode frequencies evaluated by two solution-phase peptide amide-I frequency maps proposed recently: an electrostatic potential map and an electrostatic field map. Both maps predict a set of nondegen...

In the small intestine, proglucagon is processed into the previously characterized peptide "glicentin" (proglucagon (PG) 1-69) and two smaller peptides showing about 50% homology with glucagon: glucagon-like peptide-1 and -2. It was assumed that the sites of post-translational cleavage in the small intestine of the proglucagon precursor were determined by pairs of basic amino acid residues flan...

The normal modes have been calculated for three kinds of low energy y-turn structures resulting from recent conformational energy calculations by Nkmethy. Frequencies have been computed for a y-turn, a mirror-related 7-turn, and an inverse y-turn of CH3-CO-(L-Ala),-NH-CH3, with n = 3 and n = 5 , and for certain l4 C and l5 N derivatives of the n = 3 molecule. Correlations are evident between am...

The presence or absence of peptide hormones in tissue extracts may in certain cases be demonstrated by exposing the extracts to conditions under which characteristic fragments of the polypeptide molecule in question are formed and then analyzing for such fragments. An approximate quantitation of the hormones may also be achieved thereby. In the present work the COOH-terminal fragments of polype...