ISOLATION AND PURIFICATION OF COTTONSEED 7S STORAGE PROTEIN AND ITS SUBUNITS

A rapid, simple method was developed for isolating and purifying the 7S storage globulin of cottonseed and its two major subunits. By use of small amounts of starting material, extractions were performed at 4 °C except when otherwise necessary, preparation times are kept to a minimum, and, most importantly, purification of the storage protein and its subunits is accomplished with high-performance liquid chromatography. A reverse-phase chromatography method was used to isolate and purify the subunits in one step. The 7S globulin was determined to have a molecular weight of 98K and has two subunits of 54K and 48K. There was no covalent linkage between the subunits. Results indicate that the 7S storage protein has a simpler subunit composition than previously reported. © 1990, American Chemical Society. All rights reserved.