◆Research findings by a group led by Associate Professor Kazutsugu Matsukawa of the Department of Life, Environmental, and Medical Sciences in the School of Integrated Sciences have been published in the international academic journal *Journal of Food Composition and Analysis*
Release Date:
The world's first detection of the amino acid "D-threonine (D-Thr)" in animal muscle
[Key Points of the Study]
・There are two types of enantiomers of amino acids: L-formsand D-forms; the proteins of organisms on Earth are composed primarily of L-form amino acids.
・The chiral derivatization LC-TOF/MS method developed by Human Metabolome Technologies, Inc. and others is a chemical analytical method capable of accurately distinguishing between D- and L-amino acids and detecting them with high sensitivity.
・Using this analytical method, we successfully detected D-serine, D-aspartic acid, and D-threonine in bovine muscle tissue immediately after slaughter and after aging.
・In particular, D-threonine was detected in animal muscle tissue for the first time anywhere in the world.
A joint research team comprising Associate Professor Kazutsugu Matsukawa of Kochi University, Professor Susumu Muroya of Kagoshima University, and Human Metabolome Technologies, Inc. (HMT) has identified key low-molecular-weight compounds that may shed new light on the quality and flavor of beef.
Although most of the proteins that make up our bodies are composed of L-amino acids, D-amino acids*1—which are mirror-imageisomers of L-amino acids — also exist in nature in very small amounts, and their diverse functions are attracting attention. The research team conducted a comprehensive study on the D-amino acids found in beef, a topic about which very little was previously known.
Using a highly sensitive chemical analysis technique developed in recent years (chiral derivatization LC-TOF/MS*2 ), we succeeded in accurately identifying and detecting three major D-amino acids— D-serine ( D-Ser ), D-aspartic acid ( D-Asp ), and D-threonine ( D-Thr ). Notably, this marks the first time D-Thr has been detected in animal muscle tissue worldwide. This discovery provides a crucial clue for gaining a deeper understanding of the physiology of cattle and the quality of beef.
As further research progresses into how these D-amino acids accumulate in cattle and what specific functions they perform, it is expected that this will contribute to the development of higher-quality, more flavorful beef in the future.
These research findings were published on May 10, 2025 (at 10:35 p.m. Japan Standard Time) in the international academic journal *Journal of Food Composition and Analysis*.
[Glossary]
Note 1) D-amino acids: Amino acids exist as stereoisomers known as the L-form and the D-form, which are mirror images of each other; in nature,
Proteins are composed mainly of L-amino acids. D-amino acids are found in microorganisms and some animals
It has become clear in recent years that these substances exist in trace amounts and possess unique physiological functions.
Note 2) Chiral derivatization LC-TOF/MS method: Treatment with a special reagent to distinguish between theL- and D-forms of amino acids
(derivatization) and then separated and detected using liquid chromatography–time-of-flight mass spectrometry (LC-TOF/MS).
[Paper Information]
Published in: Journal of Food Composition and Analysis
URL: (Available after 10:00 PM on May 10)
Title: Chiral derivatization and LC-TOF/MS analysis reveal the presence of D-amino acids in bovine
skeletal muscle tissue and the cultured cells
Authors: Misaki Yoshikuni (Kochi University), Kazuki Iguchi (HMT), Yasuhiro Otoguro (HMT), Shun Sato (HMT), Hirokazu Nagai (Kochi University), Yasuo Takemura (Kochi University), Shinta Sakano (Kochi University), Takuma Higuchi (Kochi University), Shuichi Sakamoto (Kochi University), Susumu Muroya (Kagoshima University), Kazutsugu Matsukawa(Kochi University)