Isolation and partial characterization of boar proacrosin

Abstract

Boar proacrosin was purified to apparent homogeneity by a three-step procedure: gel filtration on Sephadex G-50 medium, ion-exchange chromatography on CM-Cellulose 32, and reversed-phase high-performance liquid chromatography on a C4 column. The relative molecular mass (Mr) of the proacrosin estimated by gel filtration was about 70 000, whereas the results of an electrophoretic experiment on SDS-polyacrylamide gel with copolymerized casein under non-reducing conditions indicated an Mr of 55 000-60 000. The proacrosin reproducibly migrated on the gel as a double band. When purified, it remained stable at pH 8.0 for 30 min. The amino-acid composition of the homogeneous proacrosin was determined, the N-terminal amino-acid sequence being Arg-Asp-X-Ala-Thr-X-X-Gly-Pro-X-Gly-.