What proteins are typically found in the alpha 2 fraction?

The alpha 2 fraction of serum proteins is primarily associated with acute-phase reactions and the transport of various substances in the body. Haptoglobin and alpha 2 macroglobulin are the two main proteins found in this fraction.

Haptoglobin plays a critical role in binding free hemoglobin released from erythrocytes to prevent kidney damage and iron loss, while also facilitating the recycling of iron back to the body for hemoglobin synthesis. Alpha 2 macroglobulin is a large plasma protein that functions as a proteinase inhibitor, which becomes particularly prominent during inflammatory responses, helping to regulate proteolytic activity in the bloodstream.

The other options contain proteins that are not typically categorized within the alpha 2 fraction. Transferrin is primarily found in the beta fraction and is responsible for iron transport. Immunoglobulins and fibrinogen are part of the gamma fraction; immunoglobulins are involved in immune response, while fibrinogen is crucial for blood clotting. Alpha 1 acid glycoprotein and albumin are found in the alpha 1 fraction and the albumin fraction, respectively; albumin is critical for maintaining oncotic pressure and transporting various substances in the blood.