Isolation and characterization of porcine alpha 1-proteinase inhibitor. Leukocyte elastase-inhibitor complexes in porcine blood, I.

alpha 1-Proteinase inhibitor was purified from porcine blood by ammonium sulphate and Cibachron Blue-Sepharose fractionation, ion exchange chromatography on DEAE-Cellulose, gel filtration on Sephadex G-25, and zinc chelating chromatography. Thus, an inhibitor preparation with a specific activity of 1.62 IU/mg protein (enzyme: trypsin; substrate: BzArgNan) was obtained. In sodium dodecyl sulphate gel electrophoresis one protein band corresponding to a molecular mass of 67.6 kDa was found. On isoelectric focusing 6 protein bands with isoelectric points of 3.80, 3.90, 4.05, 4.20, 4.25 and 4.45 were separated. The amino acid composition was determined. The association rate constants for the inhibition of various serine proteinases were measured.