Table 1.
Kinetic Parameters for Wild-type E1p, S1-E1p and Phospho-S1-E1p
Assays | kcat (s-1) | Km for pyruvate (mM) | kcat/Km (s-1mM-1) |
---|---|---|---|
Overall | |||
WT E1p | 21 ± 1 | 41 ± 4 | 0.51 |
Y89F-α E1p | 19 ± 3 | 78 ± 13 | 0.24 |
S1-E1p | 18 ± 2 | 58 ± 5 | 0.31 |
Phospho-S1-E1p | NM | NM | - |
DCPIP | |||
WT E1p | 0.26 ± 0.02 | 8.1 ± 0.5 | 0.032 |
Y89F-α E1p | 2.7 ± 0.05 | 31 ± 5 | 0.087 |
S1-E1p | 0.31 ± 0.02 | 9.5 ± 0.8 | 0.032 |
Phospho-S1-E1p | 0.21 ± 0.01 | 281 ± 21 | 0.00075 |
Reductive acetylation | |||
WT E1p | 0.030 ± 0.002 | - | - |
Y89F-α E1p | 0.028 ± 0.002 | ||
S1-E1p | 0.028 ± 0.001 | - | - |
Phospho-S1-E1p | NM | - | - |
Phosphorylation studies on S1-E1p or Ser264-α (site 1) were carred out using a double alanine mutant S271A-α (site 2) and S203A-α (site 3). NM: not measurable.