Zeta Insulin Antibody Cocktail. Zeta’s recombinant mouse antibody cocktail contains two monoclonal antibodies that recognize Insulin, an important marker for beta-cell and insulinoma. Proinsulin, which has very little biological activity, is cleaved by proteases within its cell of origin into the active Insulin molecule and the C-terminal basic residue. Insulin enhances membrane transport of glucose, amino acids, and certain ions. Insulin also promotes glycogen storage, formation of triglycerides, and synthesis of proteins and nucleic acids. Deficiency of Insulin results in diabetes mellitus. The main storage site for Insulin is the pancreatic islets. The cocktail of insulin antibodies are important as beta-cell and insulinoma marker.