2-oxobutanoate + pyruvate + H(+) => (S)-2-ethyl-2-hydroxy-3-oxobutanoate + CO2
2-oxobutanoate + pyruvate + h(+) => (s)-2-ethyl-2-hydroxy-3-oxobutanoate + co2
2-oxobutanoate + pyruvate + H(+) => (S)-2-ethyl-2-hydroxy-3-oxobutanoate + CO2
2-oxobutanoate + pyruvate + h(+) => (s)-2-ethyl-2-hydroxy-3-oxobutanoate + co2