53363-80-7

Upstream product

• 53363-79-4 N-(tert-butoxycarbonyl)-L-prolyl-L-valine benzyl ester 
• 15761-39-4 1-(tert-butoxycarbonyl)-L-proline 
• 16652-76-9 L-valine benzyl ester p-toluenesulfonate salt 

Downstream Products

• 2854-40-2 cyclo-L-prolyl-L-valine 

Relevant academic research and scientific papers

Molecular capture and conformational change of diketopiperazines containing proline residues by epigallocatechin-3-O-gallate in water

The addition of an aqueous solution of diketopiperazine cyclo(Pro-Xxx) (Xxx: amino acid residue) to an aqueous solution of (?)-epigallocatechin-3-O-gallate (EGCg) led to precipitation of the complex of EGCg and cyclo(Pro-Xxx). The molecular capture abilities of cyclo(Pro-Xxx) using EGCg were evaluated by the ratio of the amount of cyclo(Pro-Xxx) included in the precipitates of the complex with EGCg to that of the total cyclo(Pro-Xxx) used. Stronger hydrophobicity of the side chain of the amino acid residue of cyclo(Pro-Xxx) led to a higher molecular capture ability. Furthermore, the molecular capture ability decreased when the side chain of the amino acid residue had a hydrophilic hydroxyl group. When diketopiperazine cyclo(Pro-Xxx), excluding cyclo(D-Pro-L-Ala), was taken into the hydrophobic space formed by the three aromatic A, B, and B′ rings of EGCg, and formed a complex, their conformation was maintained in the hydrophobic space. Based on nuclear Overhauser effect (NOE) measurement, the 3-position methyl group of cyclo(D-Pro-L-Ala) in D2O was axial, whereas that of cyclo(L-Pro-L-Ala) was equatorial. When cyclo(D-Pro-L-Ala) was taken into the hydrophobic space of EGCg and formed a 2:2 complex, its 3-position methyl group changed from the axial position to the equatorial position due to steric hindrance by EGCg.

Bitter Taste of Synthetic C-Terminal Tetrapeptide of Bovine β-Casein, H-Pro196-Val-Leu-Gly-Pro-Arg-Gly-Pro-Phe-Pro-Ile-Ile-Val209-OH, and Its Related Peptides

The primary structure of bovine β-casein contains the partial sequence of -Pro196-Val-Leu-Gly-Pro-Val-Arg-Gly-Pro-Phe-Pro-Ile-Ile-Val209 in the C-terminal portion.We previously reported that the synthetic C-terminal octapeptide, Arg202-Val209, is extremly bitter with its threshold value 0.004 mM, 250 times as strong as that of caffeine.To further investigate the bitter taste of the C-terminal portion of β-casein, we synthesized the C-terminal tetrapeptide, Pro196-Val209, and some its fragments.A hydrophobic hexapeptide, Pro196-Val201, was twice as bitter as caffein.The bitter taste of decapeptide, Pro200-Val209, was the same as that of Arg202-Val209.Although the tetradecapeptide, Pro196-Val209, was composed of two bitter peptides, Pro196-Val201 and Arg202-Val209, its bitter taste was weaker than that of Arg202-Val209 and its threshold value was 0.015 mM.We suggested that the increase of bitterness in peptides through the introduction of hydrophobic amino acids depended on the number of hydrophobic amino acids added.In addition, the synthetic retro analog of Arg202-Val209 (H-Val-Ile-Ile-Pro-Phe-Pro-Gly-Arg-OH) was not as bitter as Arg202-Val209.This indicated that the sequence of Arg202-Val209 is important for extreme bitterness.