Table 2.
The effect of buffers on papain adsorption on high molecular weight chitosan from solution. In brackets, bound total protein, total and specific activities are shown as the percentage of their initial values, respectively.
| Buffer System | pH | Total Protein, mg g Chitosan−1 | Protein, mg mL−1 | Activity, U mL−1 | Specific Activity, U mg Protein−1 |
|||
|---|---|---|---|---|---|---|---|---|
| 0.2 M Sodium acetate | 4.0 | 3.4 ± 0.63 | (16.8%) | 0.17 ± 0.03 | 46 ± 8.8 | (48.0%) | 271 ± 52.3 | (28.6%) |
| 4.5 | 4.7 ± 0.33 | (21.3%) | 0.21 ± 0.02 | 50 ± 8.4 | (52.8%) | 235 ± 39.5 | (24.8%) | |
| 5.0 | 6.9 ± 0.69 | (34.4%) | 0.34 ± 0.04 | 88 ± 4.6 | (93.4%) | 257 ± 13.3 | (27.1%) | |
| 5.8 | 7.1 ± 0.89 | (35.7%) | 0.36 ±0.05 | 78 ± 8.4 | (82.0%) | 218 ± 23.7 | (23.0%) | |
| 0.1 M di-potassium hydrogen phosphate | 5.8 | 5.7 ± 0.64 | (28.3%) | 0.28 ±0.03 | 26 ± 2.4 | (27.7%) | 92 ± 5.3 | (9.8%) |
| 6.0 | 5.3 ± 0.54 | (26.5%) | 0.26 ± 0.03 | 27 ± 2.0 | (28.5%) | 102 ± 7.6 | (10.7%) | |
| 6.5 | 5.0 ± 0.33 | (25.4%) | 0.25 ± 0.01 | 27 ± 2.1 | (28.6%) | 107 ± 6.7 | (11.3%) | |
| 7.0 | 4.7 ± 0.74 | (23.4%) | 0.23 ± 0.02 | 25 ± 1.8 | (26.9%) | 109 ± 5.6 | (11.6%) | |
| 7.5 | 4.3 ± 0.47 | (21.4%) | 0.21 ± 0.02 | 25 ± 1.4 | (26.4%) | 117 ± 8.2 | (12.3%) | |
| 8.0 | 4.2 ± 0.35 | (21.1%) | 0.21 ± 0.01 | 24 ± 1.3 | (25.7%) | 114 ± 10.0 | (12.0%) | |
| 0.05 M Tri-sodium borate, 0.1 M KCl | 8.0 | 8.2 ± 0.68 | (41.3%) | 0.41 ± 0.03 | 94 ± 5.1 | (99.6%) | 229 ± 8.3 | (24.1%) |
| 8.5 | 7.9 ± 1.19 | (39.7%) | 0.40 ± 0.06 | 93 ± 6.4 | (98.7%) | 235 ± 16.1 | (24.8%) | |
| 9.0 | 7.5 ± 0.73 | (37.6%) | 0.38 ± 0.04 | 93 ± 3.8 | (98.8%) | 249 ± 10.2 | (26.3%) | |
| 9.5 | 6.2 ± 1.91 | (30.1%) | 0.31 ± 0.09 | 94 ± 3.2 | (99.6%) | 305 ± 10.4 | (21.2%) | |
| 10.0 | 5.9 ± 1.08 | (29.4%) | 0.29 ± 0.05 | 94 ± 5.3 | (99.1%) | 319 ± 10.1 | (33.7%) | |
| 0.05 M Tris-glycine | 8.5 | 8.4 ± 1.5 | (42.2%) | 0.42 ± 0.08 | 92 ± 6.9 | (97.4%) | 219 ± 16.3 | (23.1%) |
| 9.0 | 7.2 ± 0.8 | (36.2%) | 0.36 ± 0.04 | 91 ± 5.2 | (96.6%) | 253 ± 14.3 | (26.7%) | |
| 0.05 M Glycine | 8.6 | 7.0 ± 0.6 | (35.1%) | 0.35 ± 0.03 | 86 ± 5.2 | (91.1%) | 246 ± 10.4 | (26.0%) |
| 9.0 | 7.2 ± 1.04 | (36.0%) | 0.36 ± 0.05 | 94 ± 7.9 | (99.8%) | 263 ± 15.3 | (27.7%) | |
| 9.5 | 8.2 ± 0.47 | (40.9%) | 0.41 ± 0.02 | 94 ± 4.2 | (99.5%) | 231 ± 9.6 | (24.3%) | |
| 10.0 | 8.1 ± 0.9 | (40.7%) | 0.41 ± 0.05 | 94 ± 5.7 | (99.0%) | 230 ± 11.7 | (24.3%) | |
| 10.5 | 7.9 ± 1.2 | (39.7%) | 0.39 ± 0.06 | 93 ± 9.7 | (98.3%) | 235 ± 24.4 | (24.8%) | |