Table 4A. Summary of Known Plant Phytases to Hydrolyze Mobilized Phytate.
| phytase
activity |
||||||||
|---|---|---|---|---|---|---|---|---|
| plant species and fraction | Ua mg–1 | μKat mg–1 | pH optim | temp (°C) | temp optim (°C) | Km (μM) | molecular wt (kDa) | ref |
| buttercup squash | – | – | 4.8 | 48 | – | – | 67 | Goel and Sharma184 |
| scallion leaves | 5.5 | 51 | – | 200 | – | Phillippy185 | ||
| sunflower | 5.2 | 55 | – | 290 | – | Agostini and Ida186 | ||
| tomato roots | 4.3 | 45 | – | 38 | 164 | Li et al.187 | ||
| 205 | 3.44 | 4.3 | – | 50 | – | – | ||
| Lilium longiflorum | 0.066 | 0.001 | 8.0 | 55–60 | 7.2 | 88 | Scott and Loewus188 | |
| maize roots | 5.7 | 0.1 | 5.0 | 40 | 71 | Hubel and Beck189 | ||
| Typha latifolia pollen | – | – | 8 | – | 17 | – | Hara et al.190 | |
| rye | – | – | 6.0 | 45 | 300 | 67 | Greiner et al.191 | |
| spelt | 262 | 4.38 | 6.0 | 45 | 400 | 68 | Konietzny et al.192 | |
| scallion (Alliumfistulosum) | 500 | 8.35 | 5.5 | 51 | 200 | 72 | Phillippy185 | |
| maize seedlings | – | – | 4.8 | 55 | 117 | 76 | Laboure et al.193 | |
| plant species | substrate | activity (EUb×10–5) | ref | |||||
|---|---|---|---|---|---|---|---|---|
| cereals (wheat, pearl millet, sorghum), legumes (mung, moth, cluster bean), oil seed crops (groundnut, sesame, mustard) | P-deficient | 29.3 | Yadaf and Tarafdar194 | |||||
| phytinc (250 mg L–1) | 29.1 | |||||||
| phytin (mg L–1) | ||||||||
| wheat (Triticumaestivum) | 50 | 2.32 | ||||||
| 100 | 3.87 | |||||||
| 150 | 5.25 | |||||||
| 200 | 7.89 | |||||||
| 250 | 9.35 | |||||||
| 300 | 9.82 | |||||||
| 500 | 9.87 |
| plant species | activity (EUb×10–5) | incubation condition | P released (mg L–1) | ref | ||||
|---|---|---|---|---|---|---|---|---|
| sorghum (Sorghum bicolor SSG-1000) | 65 | 5.4 × 10–5 EU, 500 mg kg–1 P as phytin, 2 wks | 68 | Tarafdar et al.109 | ||||
| cowpea (Vigna unguiculata RC-19) | 69 | 10.8 × 10–5 EU, 500 mg kg–1 P as phytin, 7 d | 136 | |||||
| mung bean (Phaseolus radiatus K-851) | 67 |
| phytase
activity |
||||||||
|---|---|---|---|---|---|---|---|---|
| plant species and fraction | P-fed plants | No-P plants | ref | |||||
| wheat whole root extract (soluble; mU g–1 root fw) | 4.4 ± 1.1 | 23.9 ± 1.2 | Celi and Barberis54 | |||||
| wheat total intact root (mU g–1 root fw) | 12.1 ± 4.0 | |||||||
| wheat external-root solution (mU g–1 root fw h–1) | <0.3 | <0.3 | ||||||
a
One unit (U, μmol mg–1) of phytase activity is the amount of phytase required to hydrolyze sodium phytate to produce 1 μmol P per min at 37 °C and pH 5.5.203,204
b
One EU corresponds to the amount of enzyme required to hydrolyze 1 μmol of p-nitrophenyl phosphate s–1 at pH 5.4, 35 °C.194
c
Phytin: Ca/Mg-phytate salts.