Assertion: proline | /r/AtLocation | position
Facets:
value: in the chain of amino acids
type: OTHER
Source sentences:
text: A1 and A2 beta-casein are genetic variants of the beta-casein milk protein that differ by one amino acid; a proline occurs at position 67 in the chain of amino acids that make up the A2 beta-casein, while in A1 beta-casein a histidine occurs at that position.