Table 2.
The top 15 most abundant human milk proteins after in vitro infant (0–3 months) digestion, categorized per function (N = 7).
| Colostrum (week 1) | Mature milk (week 4) | ||||
|---|---|---|---|---|---|
| Protein function | Name of proteins | Gastric (%) | Intestinal (%) | Gastric (%) | Intestinal (%) |
| Enzymes | α-lactalbumin | 22 | 0 | 20 | 0 |
| Bile salt-activated lipase | 55 | 3 | 21 | 1 | |
| Immunity | Lactoferrin | 33 | 1 | 12 | 3 |
| Ig α1-chain c-region | 12 | 2 | 84 | 2 | |
| Ig λ2-chain c-region | 16 | 6 | 46 | 6 | |
| Ig κ-chain c-region | 9 | 8 | 64 | 12 | |
| PIGR | 39 | 0 | 61 | 0 | |
| Clusterin | 46 | 0 | 43 | 0 | |
| Osteopontin | 36 | 0 | 14 | 0 | |
| β2-microglobulin | 24 | 0 | 4 | 0 | |
| Protease inhibitor | α1-antichymotrypsin | 53 | 1 | 40 | 1 |
| Transport | Serum albumin | 45 | 2 | 32 | 3 |
| β-casein | 29 | 0 | 15 | 0 | |
| αS1-casein | 39 | 0 | 2 | 0 | |
| κ-casein | 37 | 0 | 23 | 0 | |
| Based on top 15 | Total serum proteins | 33 | 2 | 37 | 2 |
| Total caseins | 35 | 0 | 13 | 0 | |
The data has been normalized to 100% per protein.