this technique was attractive for its sensitivity in that only a small amount of protein such as in 0.5 mg of tissue , especially as obtained from biopsy tissue , was needed for the separation and determination of proline ( pro ) , 4-hydroxyproline ( 4-hyp ) , 3-hydroxyproline ( 3-hyp ) , lysine ( lys ) , hydroxylysine ( hyl ) and epsilon-hydroxy-norleucine ( epsilon-ph-norleu ) , the characteristic amino acids of collagen .
C0033382
proline
C0020388
4-hydroxyproline