Casomorphin
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Casomorphin is an opioid peptide (protein fragment) derived from the digestion of the milk protein casein.[1]
Health
[edit]Digestive enzymes can break casein down into peptides that have some biological activity in cells and in laboratory animals though conclusive causal effects on humans have not been established.[1]
Some practitioners of alternative medicine claim that casomorphin may cause some of the symptoms of autism, and promote casein exclusion diets as a supposed cure, as of 2008[update] there was a lack of evidence that these diets had any effect.[2]
If opioid peptides breach the intestinal barrier, typically linked to permeability and constrained biosynthesis of dipeptidyl peptidase-4 (DPP4), they can attach to opioid receptors. Elucidation requires a systemic framework that acknowledges that public-health effects of food-derived opioids are complex with varying genetic susceptibility and confounding factors, together with system-wide interactions and feedbacks.[3]
List of known casomorphins (non-exhaustive)
[edit]β-Casomorphins 1–3
[edit]- Structure: YPF
- Chemical formula: C23H27N3O5
- Molecular weight: 425.48 g/mol
Bovine β-casomorphins 1–4
[edit]- Structure: YPFPGP
- Chemical formula: C28H35N4O6
- Molecular weight: 522.61 g/mol
Bovine β-casomorphin 1–4, amide
[edit]- Structure: YPFP-NH2
- Chemical formula: C28H35N5O5
- Molecular weight: 521.6 g/mol
Bovine β-casomorphin 5
[edit]- Structure: YPFPG
- Chemical formula: C30H37N5O7
- Molecular weight: 594.66 g/mol
Bovine β-casomorphin 7
[edit]- Structure: YPFPGPI
- Chemical formula: C41H55N7O9
- Molecular weight: 789.9 g/mol
bBCM7 is produced in when digesting bovine A1 beta-casein outside of the body using pancreatic enzymes, and inside of some animal bodies. The A2 form, which follows Ile with a Pro instead of a His, is more resistant to the release of bBCM7, presumably because the proline residue blocks the action of a carboxyl peptidase. bBCM7 has significant opioid effects when injected (and in more recent research, orally fed) into animals,[3] but human studies supporting the use of "bBCM7-free" A2 milk is still lacking.[1]
Human β-casomorphin 7
[edit]- Structure: YPFVQPI
Despite human beta-casein having a A2-like "P" after "I", human colostrum and early lactation-stage milk contains significant amounts of hBCM7. It is a much weaker opioid and the FVQ sequence renders it susceptible to further degradation.[3]
Bovine β-casomorphin 8
[edit]- Structure: YPFPGPIX
- Chemical formula (A2): C46H62N8O10
- Molecular weight (A2): 887.00 g/mol
X is H (histidine) in A1 and P (proline) in A2.
Bovine β-casomorphin 9
[edit]- Structure: YPFPGPIXN
X is H (histidine) in A1 and P (proline) in A2.
Produced from both A1 and A2. Opioid agonist, but apparently without the detrimental effect of bBCM7 in cell cultures and animal models, and in fact considered potentially beneficial.[3]
Other bioactive casein-derived peptides
[edit]References
[edit]- ^ a b c European Food Safety Authority (3 February 2009). "Review of the potential health impact of β-casomorphins and related peptides". EFSA Journal. 7 (2): 231r. doi:10.2903/j.efsa.2009.231r.
- ^ Millward, C; Ferriter, M; Calver, S; Connell-Jones, G (2008). "Gluten- and casein-free diets for autistic spectrum disorder". Cochrane Database of Systematic Reviews (2): CD003498. doi:10.1002/14651858.CD003498.pub3. PMC 4164915. PMID 18425890.
- ^ a b c d Keith, Bernard Woodford (2021). "Casomorphins and Gliadorphins Have Diverse Systemic Effects Spanning Gut, Brain and Internal Organs". Int J Environ Res Public Health. 18 (15): 7911. doi:10.3390/ijerph18157911. PMC 8345738. PMID 34360205.
- ^ Qi, N; Liu, C; Yang, H; Shi, W; Wang, S; Zhou, Y; Wei, C; Gu, F; Qin, Y (20 October 2017). "Therapeutic hexapeptide (PGPIPN) prevents and cures alcoholic fatty liver disease by affecting the expressions of genes related with lipid metabolism and oxidative stress". Oncotarget. 8 (50): 88079–88093. doi:10.18632/oncotarget.21404. PMC 5675695. PMID 29152143.
- ^ Xu, Q; Xi, H; Chen, X; Xu, Y; Wang, P; Li, J; Wei, W; Gu, F; Qin, Y (September 2020). "Milk‑derived hexapeptide PGPIPN prevents and attenuates acute alcoholic liver injury in mice by reducing endoplasmic reticulum stress". International Journal of Molecular Medicine. 46 (3): 1107–1117. doi:10.3892/ijmm.2020.4643. PMC 7387095. PMID 32705158.