Asp295 Stabilizes the Active-Site Loop Structure of Pyruvate Dehydrogenase, Facilitating Phosphorylation of Ser292 by Pyruvate Dehydrogenase-Kinase

Table 1

The specific activities of WT and mutant AtPDC E1 proteins were determined by assaying the decarboxylation of [1-¹⁴C] pyruvate in the presence of 1.0 mM K₃Fe(CN)₆ as the electron acceptor.

Enzyme	Specific activity (units/mg)	%
WT AtPDCE1	0.32±0.01	100
S292A	0.24±0.06	74
S298A	0.31±0.02	97
S292D	0.02±0.03	6
S292D/S298A	0.03±0.03	9
D295A	0.12±0.01	37
D295N	0.12±0.01	37
D295L	0.003	1
G297D	0.24±0.03	75
G297S	0.22±0.04	68