Enzyme:
\(α -1\) antitrypsin is a protein that inhibits the action of proteases and protects the lungs from the damaging action of proteases.
Used to treat arthritis
Arthritis is a disorder which occurs due to insufficient synovial fluid in the joints, which results in pain in between the joints, especially the knee joint. \(α -1\) antitrypsin is not used to treat arthritis.
Used to treat emphysema:
Emphysema is a disorder which leads to the damage of lung tissues, especially the destruction of the alveoli. It is caused due an imbalance between the enzymes (proteases) that degrade the extracellular matrix within the lungs and proteins like α -1 antitrypsin that oppose this proteolytic activity. Thus, emphysema is treated by giving recombinant α -1 antitrypsin.
Final answer: Used to treat emphysema
Summary
\(α -1\) antitrypsin:
\(α -1\) antitrypsin is a protein that protects the lungs from the unwanted protease activity which leads to emphysema.
Final answer: Used to treat emphysema.