Search by BoMiProt ID - Bomi646

Primary Information

BoMiProt ID Bomi646
Protein Name Kappa-casein
Organism Bos taurus
Uniprot IdP02668
Milk FractionWhey, MFGM, Exosome
Ref Sequence Id NP_776719.1
Amino Acid Lenth 190
Molecular Weight 21269
Fasta Sequence
Gene Name CSN3
Gene Id 281728
Protein Existence Status Reviewed: Experimental evidence at protein level

Secondry Information

Presence in other biological fluids/tissue/cells
Endogenous/Bioactive peptides - Fragment - Sequence - Effect Casoxin 6 - 33–38 - SRYPSY - Anti-Opioid Ref
Casoxin C - 25–34 - YIPIQYVLSR - Anti-Opioid Ref
Casoplatelin - 106–116 - MAIPPKKNQDK - Antithrombotic:inhibition of platelet aggragation Ref
Casoxin 4 - YPSY - Opioid agonist Ref
Protein Function Resides at the surface of the casein micelle; exists naturally; function as the interface between the calcium-sensitive caseins and milk serum; function as the “protective colloid” for micellar casein
Biochemical Properties Crosslink into disulfide-bonded polymers with a structure such that the hydrophilic tails project into the milk serum and the hydrophobic regions attach to the micelle core; chymosin cleaved k-CN at a Phe-Met bond to give a large peptide - soluble in trichloroacetic acid and an extremely insoluble para-k-CN; stable to calcium ion; at high values of pH, the disulfide bonds of «-casein undergo a cleavage; exposure of K-casein to a high alkaline environment followed by the addition of mercaptoethanol yielded a reduced form - negative nitroprusside test and failed to bind p-mercuribenzoate; x-casein forms relatively uniform aggregates of high molecular weight in inorganic salt solutions below pH 11
Significance in milk κ-casein/casein ratio may favor the bridging of proteins by calcium, resulting in faster coagulation and a firmer gel
PTMs 2.14% sialic acid
Site(s) of PTM(s)

N-glycosylation, O-glycosylation,
>sp|P02668|CASK_BOVIN Kappa-casein OS=Bos taurus OX=9913 GN=CSN3 PE=1 SV=1
Bibliography 1. Creamer LK, Plowman JE, Liddell MJ, Smith MH, Hill JP. Micelle Stability: κ-Casein Structure and Function. J Dairy Sci. 1998;81(11):3004–12.
2. Swaisgood HE, Brunner JR, Lillevik HA. Physical Parameters of k-Casein from Cow’s Milk. Biochemistry. 1964 Nov 1;3(11):1616–23.
3. Patten GS, Head RJ, Abeywardena MY. Effects of casoxin 4 on morphine inhibition of small animal intestinal contractility and gut transit in the mouse. Int Med Case Rep J. 2011;4(1):23–31.
4. JOLLÈS P, LÉVY‐TOLEDANO S, FIAT A ‐M, SORIA C, GILLESSEN D, THOMAIDIS A, et al. Analogy between fibrinogen and casein: Effect of an undecapeptide isolated from k‐casein on platelet function. Eur J Biochem. 1986;158(2):379–82.
5. Chiba H, Tani F, Yoshikawa M. Opioid antagonist peptides derived from kappa-casein. J Dairy Res [Internet]. 1989 [cited 2019 Nov 26];56(3):363–6. Available from: .
6. Yoshkawa M, Tani F, Ashikaga T, Yoshimura T, Chiba R. Purification and characterization of an opioid antagonist from a peptic digest of bovine k-casein. Agric Biol Chem. 1986;50(11):2951–4.