According to the effects of Leu, Ile, and Pro on alcohol metabo- lism (Goda et al., 1997; Yu et al., 2013), two short peptides, IPLH and IPIVLL, were chosen to be synthesized artificially. Compared with the other seven peptides, these two peptides have higher Ile, Leu, and Pro contents (Fig. 4B and C). Especially, the contents of these amino acids account for approximately 75% of IPLH. In addition, the Leu content of IPIVLL is high, and Leu is regarded as an important amino acid in alcohol metabolism (Goda et al., 1997).