Cystic fibrosis alpha 2-macroglobulin protease interaction in vitro.

alpha 2-Macroglobulin was purified from plasma of five cystic fibrosis patients and five normal controls. SDS gel electrophoresis of native alpha 2-macroglobulin from cystic fibrosis patients and normal donors showed identical subunit molecular weights, as did trypsin cleavage products. Cystic fibrosis and control alpha 2-macroglobulins were indistinguishable by isoelectric focusing and exhibited appropriate shifts in isoelectric point following binding of trypsin. The trypsin-binding capacities of control and cystic fibrosis alpha 2-macroglobulins did not differ, nor did the esterolytic activity of the trypsin-alpha 2-macroglobulin complexes.