Hexokinase IV, also known as glucokinase, is an enzyme that plays a crucial role in glucose metabolism. It is primarily found in the liver and pancreatic beta cells, where it helps convert glucose into glucose-6-phosphate, a key step in energy production and storage. Unlike other hexokinases, hexokinase IV has a high Km for glucose, meaning it only becomes active at higher glucose concentrations. This property allows it to act as a glucose sensor, regulating insulin secretion in response to blood sugar levels, thus playing a vital role in maintaining glucose homeostasis.