Casomorphin

File:Bovine β-casomorphin 7.svg

Bovine β-casomorphin 7, a casomorphin, has seven amino acids in its peptide sequence.

Casomorphin is an opioid peptide (protein fragment) derived from the digestion of the milk protein casein.<ref name=EFSA/>

Health

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.<ref name=EFSA></ref>

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, Template:As of there was a lack of evidence that these diets had any effect.<ref>Template:Cite journal</ref>

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.<ref name=pmid34360205>Template:Cite journal</ref>

List of known casomorphins (non-exhaustive)

β-Casomorphins 1–3

• Structure: Template:Mono
• Chemical formula: C₂₃H₂₇N₃O₅
• Molecular weight: 425.48 g/mol

Bovine β-casomorphins 1–4

• Structure: Template:Mono
• Chemical formula: C₂₈H₃₅N₄O₆
• Molecular weight: 522.61 g/mol

Bovine β-casomorphin 1–4, amide

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• Structure: Template:Mono-NH₂
• Chemical formula: C₂₈H₃₅N₅O₅
• Molecular weight: 521.6 g/mol

Bovine β-casomorphin 5

• Structure: Template:Mono
• Chemical formula: C₃₀H₃₇N₅O₇
• Molecular weight: 594.66 g/mol

Bovine β-casomorphin 7

• Structure: Template:Mono
• 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,<ref name=pmid34360205/> but human studies supporting the use of "bBCM7-free" A2 milk is still lacking.<ref name=EFSA>Template:Cite journal</ref>

Human β-casomorphin 7

• Structure: Template:Mono

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.<ref name=pmid34360205/>

Bovine β-casomorphin 8

• Structure: Template:Mono
• 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

• Structure: Template:Mono

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.<ref name=pmid34360205/>

Other bioactive casein-derived peptides

• Template:Mono is beneficial to mice.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>