ATPdependent

ATP-dependent refers to enzymes or cellular processes that require adenosine triphosphate (ATP) as an energy source to perform their function. In these systems, ATP binding and hydrolysis provide the energy that drives conformational changes, remodeling of substrates, or translocation along a molecule, enabling activities that would be inefficient or impossible without active energy input. Most ATP-dependent reactions are catalyzed by ATPases, proteins that bind ATP, hydrolyze it to ADP and inorganic phosphate, and couple the released energy to work on a substrate.

ATP-dependent mechanisms are widespread and diverse. They include molecular machines that convert chemical energy into mechanical work, such as motor proteins that move along actin filaments or microtubules, and ATP-driven transporters that move substrates across membranes. They also encompass chromatin remodelers that reposition nucleosomes to regulate access to DNA, and proteolytic complexes like the 26S proteasome and related AAA+ proteases that unfold substrates to feed them into proteolytic chambers. DNA helicases and translocases, which unwind or move along nucleic acids, typically rely on ATP hydrolysis as well.

The activity of ATP-dependent processes is tightly regulated and tied to cellular energy status, often reflected by the ATP/ADP ratio. Dysregulation can affect gene expression, protein homeostasis, DNA repair, and metabolism, and is implicated in various diseases. The term contrasts with ATP-independent or energy-coupled processes that rely on alternative energy sources or occur spontaneously under favorable conditions. In biology, ATPases and their associated pathways form a central class of ATP-dependent systems.