Adenülaatkinaasi

Adenülaatkinaasi, also known as adenylate kinase (AK) or myokinase, is an enzyme found in all living organisms. It plays a crucial role in cellular energy homeostasis by catalyzing the reversible transfer of a phosphate group between ATP and AMP. The reaction is as follows: ATP + AMP <=> 2 ADP. This reaction is vital for maintaining the adenylate energy charge of the cell.

Adenylate kinases belong to the phosphotransferase superfamily of enzymes. They are characterized by a conserved structure consisting of two beta-sheets forming a core domain and two alpha-helices forming a lid domain. This structure allows for the binding of both ATP and AMP. There are several isoforms of adenylate kinase in eukaryotes, each with slightly different tissue distribution and kinetic properties. For example, AK1 is primarily found in muscle and brain, while AK2 is located in the mitochondria.

The primary function of adenylate kinase is to regenerate ATP from AMP. When ATP levels are high, AMP accumulates. Adenylate kinase then converts AMP and ATP into two molecules of ADP. Conversely, when ATP levels are low, the reaction can proceed in the reverse direction, producing ATP from ADP. This buffering system helps to ensure a stable supply of ATP for cellular processes.

Dysregulation of adenylate kinase activity has been implicated in various pathological conditions, including cardiovascular diseases, neurological disorders, and cancer. Research into adenylate kinase inhibitors and activators is ongoing, with potential therapeutic applications being explored.