Which protein is also known as orosomucoid?

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

Answer: (A)

Orosomucoid is alpha-1-acid glycoprotein, a liver-produced acute-phase plasma glycoprotein. Its levels rise during inflammation, infection, trauma, or surgery, making it a marker of inflammatory states. It is an acidic, highly glycosylated protein with a molecular weight around 41–43 kDa and a high content of sialic acid, which gives it a negative charge. It also serves as a carrier for basic drugs and certain endogenous compounds, affecting their distribution and clearance. The other proteins have different roles: alpha-1-antitrypsin is an antiprotease, Gc-globulin is the vitamin D binding protein, and alpha-fetoprotein is a fetal marker.