Near-Infrared Spectrometric Determination of Di- and Tripeptides Synthesized by a Combinatorial Solid-Phase Method

Abstract

A new method based on near-infrared (NIR) spectrometry and partial least-squares analysis has been developed for the noninvasive and nondestructive determination of the identity and sequences of amino acid residues in di- and tripeptides. The di- and tripeptides were synthesized from six amino acids with similar structures (Gly, Ala, Leu, Met, Phe, Val) on two different polymer beads (bead with and without a linker) using the solid-phase peptide synthetic method. The developed NIR method is capable of determining the identity of sequences of these di- and tripeptides (with and without the Fmoc protecting group) directly on the polymer beads. It can distinguish not only dipeptides from tripeptides but also peptides with very similar structures (e.g., bead-Gly-Ala-Ala, bead-Gly-Ala-Phe, bead-Gly-Ala-Leu, bead-Gly-Ala-Val, and bead-Gly-Ala-Met). More importantly, the method is capable of distinguishing di- and tripeptides with the same amino acid residues but different sequences (e.g., bead-Gly-Leu-Val from bead-Gly-Val-Leu).

Absorption of Water by Room-Temperature Ionic Liquids: Effect of Anions on Concentration and State of Water

“…In fact, we recently developed an AOTF-based NIR spectrometer and successfully used it for a variety of spectroscopic and analytical measurem ents, including the deter- mination of sequences of peptides synthesized by solidphase combinatorial method and association constants of the inclusion complex formation between cyclodextrins and aromatic compounds, and as the detector for ow injection analysis. 25,27,31 The information presented is indeed provocative and clearly demonstrates that it is possible to use the AOTFbased NIR spectrom eter to determine concentrations and molecular states of water in RTILs. Such consideration prompted us to initiate this study, which aims to use the NIR technique to determine water absorbed by different RTILs including RTIL based on 1-butyl-3-m ethylimidazolium (…”

“…Such a spectrometer was successfully constructed in our laboratory using the acoustooptic tunable lter. [25][26][27] An acousto-optic tunable lter (AOTF) is an all-solidstate, electronic dispersive device that is based on the diffraction of light by acoustic waves in an anisotropic crystal. [28][29][30] The wavelength of the diffracted light is dependent on the frequency and the power of the applied acoustic wave.…”

Near-infrared spectroscopic method for the sensitive and direct determination of aggregations of surfactants in various media

“…1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide [EMIm] + [Tf 2 N] − was synthesized according to previously published procedure [11]. NIR spectra were taken on the home-built spectrophotometer based on an acoustooptic tunable filter similar to that used in our previous studies [12,13].…”

An ultra high throughput, double combinatorial screening method of peptide–metal binding

“…With the continuing threat to our environment by toxic metals and in particular the potentials for new radiological threats the need for selective and specific ligand discovery is a major challenge. A wide array of analytical methods based on mass spectrometry, [1][2][3] infrared thermography, 4 Fourier transform infrared spectroscopy, 5,6 nearinfrared spectroscopy 7,8 and laser-induced fluorescence imaging 9 have all been adapted for routine characterization of combinatorial libraries. However, most of these methods focus on molecular features, which can be detected via spectroscopic based techniques.…”