Casomorphin

Casomorphin is an opioid peptide (protein fragment) derived from the digestion of the milk protein casein.

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.

Although research has shown high rates of use of complementary and alternative therapies for children with autism, including gluten and/or casein exclusion diets, there was a lack of evidence that these diets had any effect.

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.

β-Casomorphins 1–3

 * Structure: H-Tyr-Pro-Phe-OH
 * Chemical formula: C23H27N3O5
 * Molecular weight: 425.48 g/mol

Bovine β-casomorphins 1–4

 * Structure: H-Tyr-Pro-Phe-Pro-OH
 * Chemical formula: C28H35N4O6
 * Molecular weight: 522.61 g/mol

Bovine β-casomorphin 1–4, amide
Also known as morphiceptin
 * Structure: H-Tyr-Pro-Phe-Pro-NH2
 * Chemical formula: C28H35N5O5
 * Molecular weight: 521.6 g/mol

Bovine β-casomorphin 5

 * Structure: H-Tyr-Pro-Phe-Pro-Gly-OH
 * Chemical formula: C30H37N5O7
 * Molecular weight: 594.66 g/mol

Bovine β-casomorphin 7

 * Structure: H-Tyr-Pro-Phe-Pro-Gly-Pro-Ile-OH
 * Chemical formula: C41H55N7O9
 * Molecular weight: 789.9 g/mol

Bovine β-casomorphin 8
(Note: There is also a form of bovine β-casomorphin 8 that has histidine instead of proline in position 8, depending on whether it is derived from A1 (His) or A2 (Pro) beta-casein.)
 * Structure: H-Tyr-Pro-Phe-Pro-Gly-Pro-Ile-Pro-OH
 * Chemical formula: C46H62N8O10
 * Molecular weight: 887.00 g/mol