👉 Protoglobulin is a type of immunoglobulin that is found in the plasma and is responsible for binding to antibodies. It consists of four chains, each containing one variable region (variable chain) and two constant regions (constant chain). The variable chains are involved in the binding of IgG1 to its epitope on the surface of the target cell, while the constant chains bind to other antigens in the plasma. Protoglobulin is a component of the complement system and plays an
