機械学習で酵素の強さと能力の高さを両立化 -加齢臭の原因物質を捉える酵素センサーへの応用に期待-

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2026-11-06 理化学研究所

理化学研究所の研究チームは、機械学習を用いて酵素の反応性と熱安定性を同時に最適化する設計技術を開発した。酵素は産業利用において高い反応活性や基質特異性に加え、熱などの環境変化に耐える安定性が求められるが、これらの性質を両立させることは難しい。研究チームは、酵母由来アルコール脱水素酵素(YADH)を対象に、加齢臭の原因物質の一つであるtrans-2-ノネナールを効率よく変換する酵素の開発に取り組んだ。約200種類の変異体を作製し、反応活性と熱安定性を測定。そのデータから機械学習モデルを構築し、両方の性能を考慮して有望な変異体を選抜した。その結果、野生型の2.2倍の反応活性を示し、熱安定性も改善した変異体を取得した。また、基質特異性を長鎖アルデヒド側へ変化させた変異体も得られた。加齢臭関連物質の検出センサーや、食品・化学品製造などに利用する産業用酵素の高性能化が期待される。

機械学習で酵素の強さと能力の高さを両立化 -加齢臭の原因物質を捉える酵素センサーへの応用に期待-
本研究の概要

<関連情報>

機械学習を用いた酵母アルコール脱水素酵素の基質特異性と熱安定性の二重最適化 Machine learning-guided dual optimization of the substrate specificity and thermostability of yeast alcohol dehydrogenase

Yuki Ogawa, Akihiko Kondo & Tomokazu Shirai
Biotechnology for Biofuels and Bioproducts  Published:01 November 2026
DOI:https://doi.org/10.1186/s13068-026-02839-2

Abstract

Background
Yeast alcohol dehydrogenase I (YADH) catalyzes the reversible reduction of aldehydes to primary alcohols. Thermostable YADH variants with broad substrate specificities at elevated temperatures are desirable for industrial biocatalysis. In this study, we aimed to alter the substrate specificity of YADH to efficiently catalyze the reduction of the non-native substrate, trans-2-nonenal, to trans-2-nonenol, while simultaneously enhancing thermostability. Residues around the substrate-binding site were identified by docking simulation and subjected to saturation and random mutagenesis. Measured activity and thermostability were used to train a machine-learning model to predict YADH variants with improved activity while maintaining thermostability.

Results
The machine learning-guided approach identified variants with improved properties. Four variants showed increased specific activity toward trans-2-nonenal compared with the wild type, and one variant also exhibited improved thermostability. The best-performing variant showed a more than twofold increase in specific activity along with retained thermal resistance. Variants that lost activity toward the native substrate acetaldehyde while gaining higher activity toward trans-2-nonenal were also obtained, indicating altered substrate specificity. These results demonstrate efficient identification of beneficial mutations from a limited dataset.

Conclusions
Overall, this study presents a machine learning–guided framework that integrates docking and multi-model evaluation for simultaneously optimizing substrate specificity and thermostability in YADH.

生物化学工学
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