Which serum protein has the largest fraction and moves the fastest in electrophoresis?

• A. Globulin
• B. Serum albumin
• C. Fibrinogen
• D. Alpha-1 antitrypsin

Answer: (B)

Serum albumin is the protein with the largest fraction in serum and it migrates the fastest during electrophoresis. It accounts for approximately 60% of the total serum protein concentration, which is significantly higher than other proteins like globulins and fibrinogen.

In electrophoresis, serum albumin is positioned closest to the anode due to its relatively low molecular weight, allowing it to migrate faster compared to larger or more complex proteins. This rapid movement is critical in differentiating serum proteins based on their sizes and charges. As a result, serum albumin consistently appears as the foremost band in electrophoresis results, distinguishing it clearly from other proteins.