Amino Acid, Peptides & Proteins

Amino acids are vital compounds as food nutrients, and approximately 20% of the human body is made up of amino acids. The concentration of amino acids in the blood (plasma) is precisely controlled; thus, variations in amino acids in the body fluid are used as indicators of body metabolism and disease. Among amino acid analysis methods, the Edman method is extensively used as an excellent method for determining the amino acid sequence of proteins and peptides. For quantitative analysis of amino acids, the derivatization methods (APDS method, PTC method, and ninhydrin method), which convert amino acids to characteristic compounds, such as fluorescent substances, and improve the selectivity and sensitivity of measurement are used.
We offer derivatization reagents, standard solutions, reagents for various automated analyzers, and buffer solutions.

Derivatization in amino acid analysis

Amino acids are compounds with less characteristic ultraviolet absorption. Thus, derivatization is needed for selective and sensitive detection of amino acids by HPLC. Typical amino acid derivatization methods include (i) pre-column derivatization in which the analyte is changed to a substance suitable for separation and detection before column separation, and (ii) post-column derivatization in which the analyte is changed to a substance suitable for detection after column separation.

In the pre-column derivatization method, the analyte is derivatized into a substance suitable for separation and detection before column separation and the product is separated and detected by HPLC. Pre-column derivatization method offers the following advantages: the reagent consumption is low; the reagents can be selected according to the detector type; and the sensitivity can be enhanced. In addition, pre-column derivatization method includes the APDS method and PTC method, and we offer derivatization reagents for these methods. Post-column derivatization is an old amino acid derivatization method, in which a derivatization reagent is reacted after column separation to guide to a detector. It offers the following advantages: the reaction can be automated, it has excellent quantitativeness and reproducibility, and it is not affected by the sample matrix when reacting with a derivatization reagent because the sample components are separated by the column before the reaction. The post-column derivatization method involves the ninhydrin method.
We offer the ninhydrin coloring solution kits, which are compatible with the automatic analyzers manufactured by Hitachi and JEOL.

Author: N. Tsurutani


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