Pyruvate Carboxylase
Contains biotin prosthetic group.
(See Figure 18.32)
Two step reaction:
Biotin carboxylase:
      E-biotin +ATP + CO2 ® E-biotin-CO2 + ADP + Pi
Transcarboxylase:
      E-biotin-CO2 + pyruvate ® E-biotin  +  oxaloacetate
Biotin is the “swinging arm” communicating
between the two active sites.