Hexokinase is an enzyme that plays a crucial role in the metabolism of glucose. It catalyzes the first step of glycolysis, converting glucose into glucose-6-phosphate. This reaction is essential for cellular energy production, as it helps trap glucose inside the cell and prepares it for further breakdown. There are several isoforms of hexokinase, each with different properties and tissue distributions. For example, hexokinase I is found in most tissues, while hexokinase IV, also known as glucokinase, is primarily present in the liver and pancreas. These variations allow the body to regulate glucose levels effectively.