Which protein has the highest concentration in the alpha-1 band during electrophoresis?

• A. a1-Antitrypsin
• B. a1-Acid Glycoprotein
• C. a-Fetoprotein
• D. Gc-Globulin

Answer: (A)

In serum protein electrophoresis, the alpha-1 band is dominated by a1-antitrypsin, a liver-produced protease inhibitor that is the principal component of this fraction. It is the most abundant protein in that region, which is why it sits as the main constituent of the alpha-1 band. The other options are present in smaller amounts or reside in different bands: a1-acid glycoprotein is an alpha-1 protein but much less abundant under normal conditions, while a-fetoprotein is a fetal/oncologic marker not typically a major adult alpha-1 component, and Gc-globulin (vitamin D-binding protein) migrates to a different fraction. Therefore, the protein with the highest concentration in the alpha-1 band is a1-antitrypsin.