Table 2. Substrate Specificity of Purified PaPPOa.
| substrate | concn (mM) | λ (nm) | ε(λ) (M–1 cm–1) | relative activity (%) |
|---|---|---|---|---|
| Monophenols | ||||
| phenol | 10 | 426 | 4300 | 0.00 ± 0.0 |
| tyramine | 10 | 395 | 1500 | 0.00 ± 0.0b |
| Diphenols | ||||
| chlorogenic acid | 10 | 475 | 511 | 738 ± 5.4 |
| 4-methylcatechol | 10 | 400 | 1720 | 378 ± 12 |
| catechol | 10 | 426 | 4300 | 100 ± 0.71 |
| caffeic acid | 1 | 481 | 591 | 336 ± 0.65 |
| l-dopa | 1 | 392 | 1240 | 5.47 ± 0.33 |
| dopamine | 10 | 395 | 1500 | 8.85 ± 0.80 |
| Triphenol | ||||
| pyrogallol | 10 | 457 | 926 | 181 ± 3.9 |
a
All measurements were performed in triplicate. Data is presented as mean ± standard deviation.
b
After storage A-PaPPO showed activity (0.0724% ± 0.0010%) on 4 mM tyramine (sodium citrate buffer, pH 4.5; Figure S2).