Peptide properties

1Top 2Function-activity relationship 3Calculated physicochemical properties 4Peptide source & Food-borne protein(s) search 5Biological/Functional activity & target protein 6Taste properties & Structure 7Preparation method 8Stability & Cytotoxicity 9Additional information 10Database cross-references 11Reference(s)

List of peptide properties

DFBP ID - DFBPOPIO0072(Opioid peptide)

DFBP ID	DFBPOPIO0072
Peptide sequence	SRYPSY
Type	Native peptide
Peptide/Function name	Opioid peptide, Casoxin-6

Function-activity relationship

Main bioactivity	Opioid activity
Otheir bioactivity	N.D

Calculated physicochemical properties

Three-letter amino acid

Ser-Arg-Tyr-Pro-Ser-Tyr

Single-letter amino acid

SRYPSY

Peptide length

Peptide mass

Experimental mass	Theoretical mass
N.D	771.81 Da ^c

Net charge

0.00 ^c

Isoelectric point (pI)

9.59 ^c

IC₅₀

N.D

pIC₅₀

N.D

GRAVY

-1.7167^c

Hydrophilic residue ratio

16.67%^c

Peptide calculator

Peptide source & Food-borne protein(s) search

Classification	Animal
Organism/Source	Bovine milk protein
Precursor protein	κ-Casein
Residue position	f(33-38)
Precursor protein(s) search	Source.1: DFBPPR7663 ---- Milk proteins ---- Kappa-casein Source.2: DFBPPR7686 ---- Milk proteins ---- Kappa-casein Source.3: DFBPPR7695 ---- Milk proteins ---- Kappa-casein Source.4: DFBPPR7715 ---- Milk proteins ---- Kappa-casein Source.5: DFBPPR8492 ---- Milk proteins ---- Kappa-casein
Link-research Inductive analysis	There are no literature reports on the discovery of this sequence in other food-source proteins.

Biological/Functional activity & target protein

Opioid activity

SRYPSY showed weak opioid antagonist activity with a IC₅₀ value of 250 μM, but the activity was increased by adding -OCH₃ at the C-terminal. As shown in table 1.

Table 1 Opioid antagonist activities of peptide.
Peptide	Receptor assay ^a, IC₅₀, μM	GPI assay ^b, A₂, μM	References
SRYPSY	250	> 500	[0]
SRYPSY-OCH₃	15	3.4	[0]

^a Radioreceptor test performed in presence of 1 nM [³H]naloxone.
^b Concentration of opioid antagonist to make the IC₅₀ value of μ-receptor specific opioid agonist Tyr-D-Ala-Gly-MePhe-Glyol (DAGO) two-fold in the guinea pig ileum assay.

Specific target protein(s)

Specific Target Protein(s):
Mu-type opioid receptor

Taste properties & Structure

Bitterness

Literature report	N.D
Bitter prediction tools	Bitter taste ^prediction

SMILES

N[C@@]([H])(CO)C(=O)N[C@@]([H])(CCCNC(=N)N)C(=O)N[C@@]([H])(Cc1ccc(O)cc1)C(=O)N1[C@@]([H])(CCC1)C(=O)N[C@@]([H])(CO)C(=O)N[C@@]([H])(Cc1ccc(O)cc1)C(=O)O

Preparation method

Mode of preparation	Synthesis peptide
Enzyme(s)/starter culture	Peptide fragments of κ-casein were synthesized with a Sam 2 peptide synthesizer (Biosearch Inc.) by the t-Boc method.

Stability & Cytotoxicity

Peptide stability

Literature report:	N.D
EHP-Tool:	Enzymatic Hydrolysis Prediction Tool (EHP-Tool)

Peptide cytotoxicity

Literature report:	N.D
Prediction:	ToxinPred

Additional information

N.D

Database cross-references

[D1]

[D2]

[D3]

[D4]

Reference(s)

Primary literature	Chiba H, Tani F, Yoshikawa M. Opioid antagonist peptides derived from kappa-casein. J Dairy Res. 1989;56(3):363-6. PMID: 2760302 DOI: 10.1017/s0022029900028818
Other literature(s)	[1] Ruoâ?JunXu. Bioactive peptides in milk and their biological and health implications[J]. Food Reviews International, 1998, 14(1):1-16. [2] Meisel H, Frister H, Schlimme E. Biologically active peptides in milk proteins.[J]. Zeitschrift Für Ernährungswissenschaft, 1989, 28(4):267. [3] Fiat A M, Jollès P. Caseins of various origins and biologically active casein peptides and oligosaccharides: Structural and physiological aspects[J]. Molecular & Cellular Biochemistry, 1989, 87(1):5-30. [4] Schlimme E, Meisel H. Bioactive peptides derived from milk proteins. Structural, physiological and analytical aspects.[J]. Nahrung, 1995, 39(1):1-20.
PubDate	1989