Study of Hydrodynamic Properties of α-1-antitrypsin from Mammalian Serum

* Author for correspondence: Professor Sharique Ahmed, Allied Health Division, College of Health Sciences, Kingdom of Bahrain. Email [email protected]. Abstract. Alpha-1-antitrypsin is an acute phase protein which is up-regulated in acute phase responses to tissue necrosis and inflammation. It belongs to a class of inhibitors called ‘’Serpins’’ (serine protease inhibitors). Human plasma contains a number of proteinase inhibitors. Among these, α-1-antitrypsin is found in the highest concentration, and is the major inhibitor for neutrophil elastase. Not only does α-1-antitrypsin deficiency lead to the disabling syndrome of pulmonary emphysema, there are other disorders too which include ANCA (antineutrophilic cytoplasmic antibody) positive Wegener’s granulomatosis, diffuse bronchiectasis, necrotizing panniculitis in α-1-antitrypsin phenotype (S), idiopathic pulmonary fibrosis and steroid dependent asthama. In view of its varied important roles in humans, a mammalian source was chosen for isolation, purification and studies into the hydrodynamic properties performed on the homogeneous fraction. Hydrodynamic properties of buffalo serum α-1-antitrypsin were determined by gel filtration, which gave a value of 3.23 nm for the stokes radius of the protein. The diffusion coefficient was found to be 6.85 x 10-7 cm2 s-1 and the frictional ratio was found to be 1.27, which together suggested a slightly aglobular conformation and excessive hydration of the isolated inhibitor molecules.