Glucagon (1-29)-[Cys(Cy5)] is derived from glucagon, which is a peptide hormone secreted by alpha cells located in the islet of Langerhans region of the pancreas. Glucagon is an essential catabolic hormone that is responsible for the regulation of blood glucose levels. Once released into the bloodstream, glucagon stimulates the production of hepatic glucose, which means it is considered to be a glucose-mobilizing agent. Excessive levels of glucagon can result in the development of hyperglycaemia, since the action of glucagon results in abnormally high blood glucose levels.

This peptide contains Cyanine 5 (Cy5), which is a widely used red fluorescent dye.