Table 1.
Kinetic parameters of A. niger AgdB and A. niger AgdA for hydrolysis of various substrates.
| Substrates | A. niger AgdB | A. niger AgdA a | ||||
|---|---|---|---|---|---|---|
| K m | k cat | k cat / K m | K m | k cat | k cat / K m | |
| (mM) | (s -1 ) | (mM -1 s -1 ) | (mM) | (s -1 ) | (mM -1 s -1 ) | |
| Maltose (Glcp-α-1,4-Glcp) | 4.3±1.0 | 46.5±5.9 | 10.8 | 3.2±0.8 | 52.3±6.1 | 16.5 |
| Kojibiose (Glcp-α-1,2-Glcp) | 3.7±0.5 | 34.7±1.9 | 9.3 | 5.2±0.1 | 16.8±0.1 | 3.2 |
| Nigerose (Glcp-α-1,3-Glcp) | 4.6±0.6 | 45.6±2.0 | 9.9 | 13.0±0.3 | 34.0±0.4 | 2.6 |
| Isomaltose (Glcp-α-1,6-Glcp) | 2.1±0.9 | 2.7±0.3 | 1.3 | 5.0±0.1 | 20.6±0.2 | 4.1 |
| Maltotriose (Glcp-α-1,4-Glcp-α-1,4-Glcp) | 4.0±0.8 | 98.5±12.1 | 24.4 | 2.0±0.4 | 62.8±5.8 | 31.7 |
| Maltotetraose (Glcp-(-α-1,4-Glcp-) 2 -α-1,4-Glcp) | 2.5±0.6 | 85.9±11.9 | 34.7 | 1.2±0.2 | 47.4±3.3 | 39.4 |
| Maltopentaose (Glcp-(-α-1,4-Glcp-) 3 -α-1,4-Glcp) | 2.5±0.5 | 96.1±12.9 | 38.4 | 1.1±0.1 | 40.4±1.3 | 36.3 |
| Maltohexaose (Glcp-(-α-1,4-Glcp-) 4 -α-1,4-Glcp) | 1.5±0.3 | 71.3±8.8 | 47.3 | 1.1±0.1 | 43.1±2.0 | 38.7 |
| Soluble starch b (Glcp-(-α-1,4-Glcp-) n -α-1,4-Glcp) | 0.7±0.1 | 47.4±3.1 | 67.7 | 3.0±0.5 | 184.3±16.5 | 62.0 |
K m and k cat are shown with standard errors (SE). a Kinetic parameter of A. niger AgdA cited from a previous report. 19) b Weighted average molecular weight of soluble starch was 8,778 determined by gel permeation chromatography.