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 - DFBPOPIO0008(Opioid peptide)

DFBP ID	DFBPOPIO0008
Peptide sequence	RYLGYL
Type	Native peptide
Peptide/Function name	Opioid peptide, Exorphin, Exomorphin, α-Casein exorphin^[3]

Function-activity relationship

Main bioactivity	Opioid activity
Otheir bioactivity	N.D

Calculated physicochemical properties

Three-letter amino acid

Arg-Tyr-Leu-Gly-Tyr-Leu

Single-letter amino acid

RYLGYL

Peptide length

Peptide mass

Experimental mass	Theoretical mass
N.D	783.91 Da ^c

Net charge

0.00 ^c

Isoelectric point (pI)

9.59 ^c

IC₅₀

N.D

pIC₅₀

N.D

GRAVY

0.0167^c

Hydrophilic residue ratio

50%^c

Peptide calculator

Peptide source & Food-borne protein(s) search

Classification	Animal
Organism/Source	Bovine milk protien
Precursor protein	α_s1-Casein
Residue position	f(90-95)
Precursor protein(s) search	Source.1: DFBPPR7688 ---- Milk proteins ---- Alpha-S1-casein Source.2: DFBPPR7694 ---- Milk proteins ---- Alpha-S1-casein Source.3: DFBPPR7717 ---- Milk proteins ---- Alpha-S1-casein Source.4: DFBPPR8488 ---- Milk proteins ---- Alpha-S1-casein Source.5: DFBPPR22351 ---- Animal proteins ---- Transmembrane protein 168
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

The peptide RYLGYL was specific ligands for the u- and δ-receptor. It showed opioid activity as measured by several standard assay procedures. Whereas RYLGYL exhibits a somewhat weaker but still substantial affinity. As shown in table 1.

Table 1 Opioid activity of peptide
Peptide	Opiate assay (IC₅₀, uM)/Activity
Peptide	Displacement of [³H]DALAMID from rat brain membranes	Displacement of [³H]DHM from rat brain membranes	Inhibition of adenylate cyclase in homogenates of NG108-15 cells	Inhibition of electrically stimulated mouse vas deferens
Isolated α-casein exorphin ^a	－	3.8	0.3	11.0
RYLGYL	3.6	12.0	2.0	70.0
RYLGYL	Opioid agonist ^[3]

^a Opioid peptides from pepsin hydrolysates of α-casein.

Specific target protein(s)

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

Taste properties & Structure

Bitterness

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

SMILES

N[C@@]([H])(CCCNC(=N)N)C(=O)N[C@@]([H])(Cc1ccc(O)cc1)C(=O)N[C@@]([H])(CC(C)C)C(=O)NCC(=O)N[C@@]([H])(Cc1ccc(O)cc1)C(=O)N[C@@]([H])(CC(C)C)C(=O)O

Preparation method

Mode of preparation	Enzymatic hydrolysis
Enzyme(s)/starter culture	Hydrolysis with Pepsin.

Stability & Cytotoxicity

Peptide stability

Literature report:	The peptide was resistant to hydrolysis by trypsin and homogenates of rat brain membranes, but was partially inactivated by chymotrypsin and subtilisin.
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	Loukas S, Varoucha D, Zioudrou C, Streaty RA, Klee WA. Opioid activities and structures of alpha-casein-derived exorphins. Biochemistry. 1983 Sep 13;22(19):4567-73. PMID: 6313043 DOI: 10.1021/bi00288a034
Other literature(s)	[1] Park Y W. Bioactive Components in Milk and Dairy Products[M]. 2009. [2] Migliore-Samour D, Floc'H F, Jollès P. Biologically active casein peptides implicated in immunomodulation[J]. Journal of Dairy Research, 1989, 56(3):357. [3] Kostyra E, Sienkiewiczszłapka E, Jarmołowska B, et al. Opioid peptides derived from milk proteins.[J]. Polish Journal of Food & Nutrition Sciences, 2004. [4] Yoshikawa M., Tani F., Yoshimura T., Chyba H., Opioid peptides from milk proteins. Agric. Biol. Chem., 1986, 50, 2419–2421. [5] Meisel H. Overview on Milk Protein-derived Peptides[J]. International Dairy Journal, 1998, 8(5–6):363-373. [6] 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. [7] Schlimme E, Meisel H. Bioactive peptides derived from milk proteins. Structural, physiological and analytical aspects.[J]. Nahrung, 1995, 39(1):1-20.
PubDate	1983