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Updated: Sep 25, 2026

Peptide-derived Method to Transport Genes and Proteins Across Cellular and Organellar Barriers in Plants
Published on: December 16, 2016
Delta opioid peptides derived from plant proteins
M Yoshikawa1, M Takahashi, S Yang
1Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011, Japan. yosikawa@kais.kyoto-u.ac.jp
Abstract:
Opioid peptides showing selectivity for delta receptor have been isolated from enzymatic digests of plant proteins. Five peptides were derived from wheat gluten, and named gluten exorphins A5, A4, B5, B4 and C. Two opioid peptides were also released from spinach ribulose-bisphosphate-carboxylase/oxygenase (Rubisco), and named rubiscolins-5 and -6. Among them, gluten exorphin 5A (Gly-Tyr-Tyr-Pro-Thr) and rubiscolin 6 (Tyr-Pro-Leu-Asp-Leu-Phe) improved learning performance in step-through type passive avoidance test after post-training oral administration in mice at doses of 300 mg/kg and 100 mg/kg, respectively, which are smaller than those required for antinociceptive activity.
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