Abstract: The present invention provides compositions and methods useful for assaying binding of compounds to the hERG K+ channel. According to a method of the present invention, a compound of interest is added to the hERG K+ channel in the presence of a selenium analog of a competitive inhibitor of the hERG K+ channel. Next, the amount of the selenium analog of the competitive inhibitor that bound to the hERG K+ channel is quantified using mass spectrometry. The quantified amount can then be used to determine the amount of the compound of interest that bound to the hERG K+ channel. A selenium analog of any competitive inhibitor of the hERG K+ channel may be used according to the present invention, including but not limited to selenium analogs of the small molecule dofetilide; the peptide BeKm-1; or a combination of both.

Abstract: The present invention provides compositions and methods useful for assaying binding of compounds to the hERG K+ channel. According to a method of the present invention, a compound of interest is added to the hERG K+ channel in the presence of a selenium analog of a competitive inhibitor of the hERG K+ channel. Next, the amount of the selenium analog of the competitive inhibitor that bound to the hERG K+ channel is quantified using mass spectrometry. The quantified amount can then be used to determine the amount of the compound of interest that bound to the hERG K+ channel. A selenium analog of any competitive inhibitor of the hERG K+ channel may be used according to the present invention, including but not limited to selenium analogs of the small molecule dofetilide; the peptide BeKm-1; or a combination of both.

Abstract: The present invention relates to a method for high performance peptide mapping of a polypeptide with one or more cysteine residues by subjecting the polypeptide to sulfitolysis in the peptide mapping procedure.

Abstract: A method is provided for quantitatively monitoring the deprotection and coupling reactions employed in the solid phase synthesis of peptides. The method entails synthesizing a peptide on a support matrix that has a first marker associated therewith. The amino acids employed in the peptide synthesis procedure have a second marker attached thereto, which can be the blocking group used for the amino acid. After the coupling or deprotection step a portion of the support matrix is processed to release first and second identifers from the first and second markers, respectively. The completeness of the coupling or deprotection step can be determined by comparing the relative amounts of the detected first and second identifiers. Novel compositions of matter are used in or produced during this method, including support matrixes having pyrolyzable markers attached thereto.

Abstract: A method is provided for quantitatively monitoring the deprotection and coupling reactions employed in the solid phase synthesis of peptides. The method entails synthesizing a peptide on a support matrix that has a first marker associated therewith. The amino acids employed in the peptide synthesis procedure have a second marker attached thereto, which can be the blocking group used for the amino acid. After the coupling or deprotection step a portion of the support matrix is processed to release first and second identifers from the first and second markers, respectively. The completeness of the coupling or deprotection step can be determined by comparing the relative amounts of the detected first and second identifiers. Novel compositions of matter are used in or produced during this method, including support matrixes having pyrolyzable markers attached thereto.

Abstract: The preparation of [1-(.beta.-mercapto-.beta.,.beta.-cyclopentamethylenepropionic acid)-2-(O-ethyl-D-tyrosine)-4-valine-8-arginine-9-desglycine]vasopressin by oxidation of the corresponding dimercaptan is improved by using a copper II salt.