Studies of Bitter Peptides from Casein Hydrolyzate. III. Bitter Taste of Synthetic Analogs of BPIa (Arg–Gly–Pro–Pro–Phe–Ile–Val) Containing d-Proline or Glycine in Place of l-Proline

Abstract

In order to elucidate the relationship between chemical structure and bitter taste of BPIa, the analogs containing d-proline or glycine in place of the l-proline in the 3- or 4-positions were synthesized. The bitter taste of [d-Pro3,4]–BPIa (ld-d), [d-Pro3]–des–Pro3–BPIa (2d), and [Gly3]–des–Pro3–BPIa lacking the l-proline residue was much weaker than that of the peptides containing the l-proline, BPIa (1l-l), 1l-d, 1d-l, and 2l. The CD curves of these analogs and BPIa were measured in water. The results suggested that the bitter taste of BPIa is caused by the spatial structure attributed to the l-proline residue.

Studies on a Model of Bitter Peptides Including Arginine, Proline and Phenylalanine Residues. I. Bitter Taste of Di- and Tripeptides, and Bitterness Increase of the Model Peptides by Extension of the Peptide Chain

“…Further, we determined that a spatial structure of BPI a is required in order for it to exhibit bitternessy,I3,I7 ,18) This characteristic spatial structure is likely to be caused by a proline residue in the center of BPIa. 13 ) From these results, we found that arginine, proline and hydrophobic amino acid are indispensable for exhibiting a strongly bitter taste.…”

Quantitative Structure−Activity Relationship Study of Bitter Peptides

“…Spatial configuration for the adjacency of bifunctional sites in the amino acid sequence is provided in some peptides by the presence of Pro. The imino ring of the L-Pro molecule induced bitterness of Pro-containing peptides through a conformational alteration leading to folding of the peptide backbone (25,26) and formation of a ball-like shape instead of a helix conformation (11). For example, the bitter taste of BPIa (Arg-Gly-Pro-Pro-Phe-Ile-Val) from casein hydrolyzate was due to the spatial structure attributed to the L-Pro at the 3-position (26).…”

“…The imino ring of the L-Pro molecule induced bitterness of Pro-containing peptides through a conformational alteration leading to folding of the peptide backbone (25,26) and formation of a ball-like shape instead of a helix conformation (11). For example, the bitter taste of BPIa (Arg-Gly-Pro-Pro-Phe-Ile-Val) from casein hydrolyzate was due to the spatial structure attributed to the L-Pro at the 3-position (26). For the octapeptide Arg-Gly-Pro-Phe-Pro-Ile-Ile-Val, the location of a hydrophobic amino acid in the L-configuration between the two Pro residues was important to maintain the folded structure of the peptides to produce a strong bitterness (27).…”

L-Ornithyltaurine, a new salty peptide

“…In addition, many workers have synthesized various bitter peptides and reported the relationship between bitter taste and chemical Department of Fermentation Technology, Faculty of Engineering, Hiroshima University, Shitami Saijo-cho, Higashihiroshima 724, Japan. structure (Shiba and Nunami, 1974; Matoba and Hata, 1972;Okai, 1977;Fukui et al, 1983; Otagiri et al, 1983; Miyake et al, 1983). As for sweet peptides, aspartame (H-Asp-Phe-OMe) and its derivatives have been studied for the development of artificial sweetening agents (Mazur et al, 1969(Mazur et al, ,1970(Mazur et al, ,1973Fujino et al, 1973Fujino et al, ,1976Ariyoshi et al, 1974;Ariyoshi, 1976Ariyoshi, , 1980Miyoshi et al, 1978).…”