Table 2. Comparison of KM values for AlaAT and GGAT enzymes.
| Organism | KM (mM) | Previous KM (mM) | Source of AlaAT | Reference | ||||||
| Alanine | 2-Oxoglutarate | Pyruvate | Glutamate | Alanine | 2-Oxoglutarate | Pyruvate | Glutamate | |||
| Arabidopsis AlaAT1 | 2.4 | 0.1 | 0.1 | 2.5 | 1.5 | 0.2 | NA | NA | A. thaliana leaves (protein purified) | Wiśniewski et al., (2006) |
| Barley AlaAT | 5.6 | 0.2 | 0.1 | 4.9 | 17 | 5 | 0.1 | 1 | Barley roots (protein purified) | Good and Muench (1992) |
| Arabidopsis GGAT1 | 1.9 | 0.2 | 0.6 | 0.2 | 4.8 | 0.3 | 0.3 | 2.0 | E. coli (recombinant expression) | Liepman and Olsen (2003) |
| NA | NA | NA | 1.2 | A. thaliana leaves (protein purified) | Wiśniewski et al., (2006) | |||||
| Arabidopsis GGAT2 | 1.2 | 8.8 | 18.5 | 0.2 | 3.6 | 0.5 | 0.4 | 3.3 | E. coli (recombinant expression) | Liepman and Olsen (2003) |
| Pyrococcus furiosus AlaAT | 4.0 | 0.02 | 16.5 | 0.9 | 3.2 | 1.1 | 4.7 | 5.6 | E. coli (recombinant expression) | Ward et al., (2000) |
KM values obtained during this study were compared with previous KM values from various published sources. Discrepancies between kinetic values can be attributed partially to differences in procedure as well as differences in original data collection. Nevertheless, significant differences in KM values for all enzymes are evident. Variation amongst results highlights the benefit of using one system and one procedure when comparing kinetic data from several different enzymes. (NA = no data available from previous studies.).