PREPARATION OF CONCANAVALIN A FREE PURIFIED ALPHA-1-ANTITRYPSIN

A simple technique is described to remove traces of concanavalin A (Con A) from human α-1-antitrypsin (α-1-AT) purified on commercially available Con A-Sepharose. The α-1-AT was fractionated from serum by ammonium sulfate precipitation followed by chromatography on DEAE-cellulose, Con A-Sepharose, and activated thiol-Sepharose at 4°C with solution pH ranges of 7.4-7.6 in all steps. Contaminating Con A was easily removed by binding α-1-AT through the reactive sulfhydryl group to the activated thiol-Sepharose gel and washing away the contaminating Con A with a solution of methyl-α-d-glucopyranoside before final elution of bound α-1-AT. This simple procedure yields purified α-1-AT free of traces of Con A. The α-1-AT was obtained in overall yields of 40-48% from serum with an average molecular weight of 53,500 ± 3000 determined on 15% disc polyacrylamide gels containing sodium dodecyl sulfate (SDS). The isolated α-1-AT exhibited unaltered Pi M phenotype compared to serum α-1-AT but contained traces of several other serum proteins. © 1979 Academic Press, Inc.