Table 2.
Amino acid analysis of collagen after noncollagenous protein removal with different NaOH concentrations.
| Amino acids | 0.1 M NaOH | 0.5 M NaOH | 1.0 M NaOH | 1.5 M NaOH |
|---|---|---|---|---|
| Aspartic acid | ND | ND | 0.196 | 0.028 |
| Threonine | ND | ND | ND | ND |
| Serine | ND | 0.045 | 0.052 | 0.23 |
| Glutamic acid | ND | ND | 0.104 | ND |
| Glycine | ND | 0.104 | 0.315 | 1.23 |
| Alanine | ND | ND | 0.222 | 0.316 |
| Cystine | 0.641 | 0.653 | 1.510 | 2.18 |
| Valine | ND | ND | 0.201 | 0.554 |
| Methionine | ND | ND | 0.050 | ND |
| Isoleucine | ND | ND | ND | ND |
| Leucine | ND | ND | ND | ND |
| Tyrosine | ND | ND | 1.541 | ND |
| Phenylalanine | ND | 0.997 | 1.210 | 2.006 |
| Lysine | ND | ND | ND | ND |
| Histidine | ND | ND | ND | ND |
| Arginine | ND | ND | ND | ND |
| Proline | ND | ND | ND | ND |
| Total (μg/mL) | 0.641 | 1.798 | 5.401 | 6.546 |
ND: not detected.