Isolation and Partial Characterization of Arachin-P6

A method is described for the isolation of gram quantities of relatively pure arachin from the peanut seed. The isolate was named arachin-P6. Arachin-P6 was homogeneous by immunodiffusion, Immunoelectrophoresis and chromatography on DEAE-cellulose and Sephadex gels. The isolate contained relatively high contents of glutamic acid and arginine. [α']25 D, δC- and K for arachin-P6 were -36.5, 213.2 mμ and -11 × 108, respectively; the parameters a0 and b0 of the moffitt plot for the isolate were -240.5 and 3.2, respectively. In sedimentation analysis arachin-P6 showed one major component (accounting for 93% of the protein) with s20, w of 13.1s (s°20, w= 13.36 S) and two minor components with s20, w values of 19.5 S and 8.09 S. Disc gel electrophoresis of the isolate demonstrated two major and three minor components; the preparation did not contain any basic protein. Our results clearly show that the two previously reported2, 3 isolates of arachin, one prepared by a method based on fractional precipitation with (NH4)2SO4 and the other prepared by a method involving selective removal of impurities by precipitation with heat, once considered identical by the other workers3 indeed represent two distinct preparations of this protein.