Figure 4. Composition and allosteric activation of bacterially expressed AMPK complexes.

(A) Analysis of α1β1γ1, α2β2γ1 and α2β2γ3 complexes by SDS/PAGE and Coomassie Blue staining; (B) allosteric activation of α1β1γ1, α2β2γ1 and α2β2γ3 complexes by AMP. Assays in (B) were performed in the presence of 5 mM ATP and 9.8 mM MgCl₂ and the data fitted to the same equation as in Figure 3. Note added in proof: The band marked “?” in (A) has been identified by mass fingerprinting to be the bacterial protein arnA (UNIPROT P77398).