Fig. (2) SDS-PAGE and native gel analysis of AMPK α₁β₁γ₁ and α₂β₁γ₁. Lanes 1 and 7: native (non-denaturing) PAGE samples. Lanes 2 and 8: Invitrogen Benchmark protein ladder. Lanes 3 – 6: AMPK α₁β₁γ₁ loaded at 1, 2, 5, or 10 µg / lane. Lanes 9 – 12: AMPK α₂β₁γ₁ loaded at 1, 2, 5, or 10 µg / lane. The GST-tagged α₁ and α₂ subunits have calculated molecular weights of 90.8 and 91.4 kDa, respectively. The GST-tagged β₁ and 6-His-tagged γ₁ subunits have calculated molecular weights of 57.8 and 41.7 kDa, respectively.