An amino acid-specific binder selectively binds to a binding amino acid. A binder complex selectively identifies the binding amino acid and includes an adjunct attached to the amino acid-specific binder. The adjunct includes a taggant, protein, substrate, or chemical modifier. Selectively identifying an N-terminal amino acid includes anchoring a C-terminal end; contacting an N-terminal amino acid of the anchored analyte with the binder complex; selectively binding when the N-terminal amino acid includes the binding amino acid; producing, by the taggant of the tagged complex, a taggant signal; detecting the taggant signal; and identifying the N-terminal amino acid based on the taggant signal.

An amino acid-specific binder selectively binds to a binding amino acid. A binder complex selectively identifies the binding amino acid and includes an adjunct attached to the amino acid-specific binder. The adjunct includes a taggant, protein, substrate, or chemical modifier. Selectively identifying an N-terminal amino acid includes anchoring a C-terminal end; contacting an N-terminal amino acid of the anchored analyte with the binder complex; selectively binding when the N-terminal amino acid includes the binding amino acid; producing, by the taggant of the tagged complex, a taggant signal; detecting the taggant signal; and identifying the N-terminal amino acid based on the taggant signal.

The present invention provides a method for specifically cleaving a C-C bond of a peptide backbone and/or a side chain of a protein and a peptide, and a method for determining amino acid sequences of protein and peptide. A method for specifically cleaving a C-C bond of a peptide backbone and/or a side chain bond of a protein or a peptide, comprising irradiating a protein or a peptide with laser light in the presence of at least one hydroxynitrobenzoic acid selected from the group consisting of 3-hydroxy-2-nitrobenzoic acid, 4-hydroxy-3-nitrobenzoic acid, 5-hydroxy-2-nitrobenzoic acid, 3-hydroxy-5-nitrobenzoic acid, and 4-hydroxy-2-nitrobenzoic acid. A method for determining an amino acid sequence of a protein or a peptide, comprising irradiating a protein or a peptide with laser light in the presence of the above specific hydroxynitrobenzoic acid to specifically cleave a C-C bond of a peptide backbone and/or a side chain bond, and analyzing generated fragment ions by mass spectrometry.

Methods of sequencing a protein using a novel digestion-on-emitter technology are provided.

Methods of sequencing a protein using a novel digestion-on-emitter technology are provided.

Provided are a method for industrially advantageously producing a highly purified pentapeptide and an intermediate thereof. A compound represented by the following formula (1) or a salt thereof: ##STR00001##
wherein R.sup.1 represents an alkyl group or an aralkyl group.

A sample is dissolved in a reagent 4 containing an organic solvent in a conversion vessel 11. A gas is supplied from a first gas supply part into the conversion vessel 11 via a reagent introduction tube 17, and thus the interior of the conversion vessel 11 is pressurized. A gas is supplied from a second gas supply part into the reagent 4 in the conversion vessel 11 via a reagent discharge tube 18, and thus gas bubbles 41 are formed in the reagent 4.

Provided are a method for industrially advantageously producing a highly purified pentapeptide and an intermediate thereof.

A compound represented by the following formula (1) or a salt thereof:

##STR00001##

wherein R.sup.1 represents an alkyl group or an aralkyl group.

Present invention refers to a novel and improved method of derivatization and detection of amino acid sequence and/or identification of proteins, peptides by a new derivatization compound. Precisely, the method discloses a novel approach to derivatization of peptides or proteins by compounds comprising two or more sulfonyl groups and analysis of derivatized analytes in negative mode of operation of mass spectrometer. This method allows unambiguous analysis of amino acid sequence of long-chain peptides/proteins. Also, the invention discloses a novel synthesis procedure of 5-formyl-benzene-1,3-disulphonic acid as derivatization compound.

A first aspect of the invention relates to a method for removing a terminal amino acid from a peptide. The method comprises providing a reaction cell configured as an electrochemical transducer translating an applied voltage or current into a change of pH within the reaction cell, the reaction cell having arranged therein a sample surface functionalized with moieties suited for the sequential removal of an amino acid from a terminus of the peptide, the terminus being the N-terminus or the C-terminus of the peptide. After introducing the peptide into the reaction cell, the pH in the reaction cell is adjusted to attach the peptide with the terminus to the sample surface. Non-attached peptide is then removed from the reaction cell and the pH in the reaction cell is adjusted to separate an amino acid at the terminus of the peptide from the peptide and to immobilize the amino acid on the sample surface. Further aspects of the invention relate to a method for sequencing a peptide and to a microfluidic device.