AMPK or Adenosine Monophosphate-Activated Protein Kinase is an enzyme which plays an important role in cellular energy homeostatis. It belongs actually to a highly conserved eukaryotic protein family. Its Orthologues are SnRK1 and SNF1 in plants and yeasts. It also compose of 3 proteins that make a functional enzyme together, conserved from yeast to humans. It's expressed in many tissues including skeletal muscles, brain and liver.

The net effect of AMPK Activator is stimulating hepatic fatty acid oxidation, stimulation of skeletal muscle fatty acid oxidation as well as glucose uptake, ketogenesis, lipogenesis, and triglyceride synthesis, inhibition of cholesterol synthesis, modulation of insulin secretion by pancreatic beta-cells and lastly, inhibition of adipocyte lipolysis and lipogenesis. It must not be confused with cyclic AMP Activated Protein Kinase or also known as Protein Kinase A.

AMPK is heterotrimeric protein complex that's formed by subunits a, b, and y. Each of the said subunit takes on specific role in both activity and stability of AMPK. Specifically, the y subunit consist of 4 particular Cystathionine Beta Synthase or CBS domains which gives AMPK its capability to detect shifts sensitively which is otherwise known as Bateman domains. Binding of one AMP to Bateman domain increases its binding affinity of second AMP to other Bateman domains.

As AMP binds the said domains, the y subunit is undergoing a conformational change that exposes the catalytic domain found on a subunit. It's in this catalytic domain in which AMPK becomes activated when phosphorylation will take place at Threonine-172 by upstream AMPK kinase. The subunits may also be found in different isoforms like for instance, the ?subunit may exist either as y1, y2, or even y3 isoform while the b subunit can exist as b1 or b2 isoform while the a subunit can exist as either the a1 or a2 isoform.

Because of the presence of isoforms of components, there are twelve versions of AMPK in mammals and each has different tissue localization as well as functions under different conditions. AMPK is also regulated allosterically and is by post-translational modification that work together. If ever residue T172 of AMPk's a-subunit is the phosphorlyated, AMPK is activated. The access to that particular residue by phosphatases is then blocked if ADP or AMP can block access for and the ATP can displace ADP and AMP. That residue is phosphorlyated by at least 3 kinases, which all works in a complex with MO25 and STRAD, TGFb-activated kinase 1, calcium-/calmodulin-dependent kinase kinase 2 and also, dephosphorylated by three phosphatases which includes protein phosphatase 2C (PP2C), Mg2+-/Mn2+-dependent protein phosphatase 1E and protein phosphatase 2A.