Q.4 Antitrypsin is
(a) an antacid

(b) an enzyme
(c) used to treat arthritis

(d) used to treat emphysema

(d) $\alpha$-antitrypsin is a protease inhibitor that is produced by the introduction of specific sequence of DNA (or genes) which codes for a particular product in the transgenic animals. It is used to treat emphysema as it inhibits the enzymes of inflammatory cells that contributes to the respiratory complications.