Effect of gallic acid on peptides released by trypsin digestion of bovine α-casein

Ping Lai, Atsushi Okazawa, Yoshihiro Izumi, Takeshi Bamba, Eiichiro Fukusaki, Masaaki Yoshikawa, Akio Kobayashi

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


In this study, the effects of gallic acid (GA) on trypsin digestion of commercial α-casein (α-CN), which contains αs1-CN and αs2-CN, and the peptides released during digestion were investigated. Gallic acid showed no effect on the initial rate of digestion. However, the apparent degree of hydrolysis achieved its maximum value after 1 h, then decreased in the presence of GA, suggesting the cross-linking between peptides once released from α-CN during digestion. In the presence of GA, three peaks derived from αs1-CN disappeared and three new peaks appeared in high-performance liquid chromatography (HPLC) analysis. In these peptides, two Met residues corresponding to the Met135 and Met196 in αs1-CN were oxidized to Met sulfoxide residues. The oxidation of Met196 was quicker than that of Met135. The inhibitory activity of TTMPLW (αs1-CN 193-199) against angiotensin I-converting enzyme was reduced slightly by the oxidation of its Met residue.

Original languageEnglish
Pages (from-to)259-267
Number of pages9
JournalJournal of Bioscience and Bioengineering
Issue number3
Publication statusPublished - Mar 2013
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology


Dive into the research topics of 'Effect of gallic acid on peptides released by trypsin digestion of bovine α-casein'. Together they form a unique fingerprint.

Cite this