Glükokinaasiga

Glükokinaasiga is a Finnish term referring to glucokinase, an enzyme. Glucokinase (GCK) is a specific enzyme found primarily in the liver and pancreatic beta cells in humans and other vertebrates. Its main function is to catalyze the phosphorylation of glucose to glucose-6-phosphate. This initial step is crucial for glucose metabolism, initiating its breakdown for energy or storage as glycogen.

In the liver, glucokinase plays a significant role in regulating blood glucose levels after a meal. When blood glucose rises, glucokinase becomes active, converting excess glucose into glucose-6-phosphate. This intermediate can then be stored as glycogen, thus lowering blood glucose. Conversely, when blood glucose levels fall, glucokinase activity decreases, allowing stored glycogen to be broken down and released into the bloodstream.

In the pancreatic beta cells, glucokinase acts as a glucose sensor. Its activity directly correlates with blood glucose concentration. When glucose enters beta cells, glucokinase phosphorylates it, leading to an increase in intracellular ATP. This ATP rise triggers the closure of ATP-sensitive potassium channels, initiating a cascade of events that ultimately results in the release of insulin. Therefore, glucokinase is essential for the body's response to elevated blood glucose by promoting insulin secretion.

Mutations in the GCK gene can lead to various forms of diabetes mellitus, including monogenic forms of diabetes like maturity-onset diabetes of the young (MODY2) and neonatal diabetes. These mutations can impair the enzyme's function, leading to either reduced insulin secretion or altered hepatic glucose uptake, both contributing to hyperglycemia.