Isolation and characterization of the 10S fraction of poppy seed proteins

The high mol. wt. protein fraction was isolated to homogeneity by slow dialysis of 1M NaCl extract of poppy seed meal. The S20,w value of the protein was 10.1S and mol. wt. 215 000. The intrinsic viscosity was 3.5 ml/g, suggesting a compact globular structure for the protein. SDS-PAGE gave 6 nonidentical subunits. The protein had an absorption max. at 278 nm and fluorescence emission max. at 325 nm. It was rich in aspartic and glutamic acids, arginine, and methionine. It also contained 1.15% carbohydrate and very little phosphorus (0.01%). The circular dichroism spectrum showed that the secondary structure of 10S protein consisted of mainly beta-structure and aperiodic structure with little alpha-helix. The protein was highly resistant to hydrolysis by proteolytic enzymes.