Characterization of the proteins of pili nut (Canarium ovatum, Engl.)

The storage proteins of the pili nut (Canarium ovatum, Engl.), quantitatively extracted using the modified Osborne protein fractionation scheme, revealed that the aqueous soluble globulin was the main storage protein within the kernel (i.e., >> 60.3%). Further physicochemical characterization of this aqueous soluble globulin revealed that it existed in an 11S like form and was composed of two main subunits of 22,600 and 31,600 Da. These subunits were found to be disulfide-linked (in a 1:1 ratio) forming intermediary subunits (i.e., dimers) with a molecular weight of approximately 52,600 Da. The overall molecular weight of the 11S globulin was determined to be approximately 300,000 Da suggesting that the globulin possessed a dodecameric-like structure of 6 dimers for a total of 12 subunits. Using differential scanning microcalorimetry, the denaturation temperature of the globulin was shown to occur at 89.3 degrees C. Overall, the pili nut 11S globulin was found to possess many similar physicochemical properties to those of other 11S oilseed globulins.