Sample preparation for protein extraction is a critical first step to achieve reliable analytical results. In this study we compared different bead kits using two different suspension liquids and two kinds of plant organ, soft and hard seeds, namely peanut and rice, respectively.
Table 1. Protein extraction efficiency as a percentage of total protein content, using saline extraction buffer. Extraction efficiency is based on the theoretical amount of protein, 25.8g, 6.12g/100g of peanut, rice respectively. (USDA National Nutrient Database for Standard Reference Release 26, Feb 7, 2014. http://ndb.nal.usda.gov/ndb/foods). **A MudPIT method for LC-MS/MS was used to identify proteins from rice (Delahunty CM, Yates JR. MudPIT: multidimensional protein identification technology. Biotechniques 2007; 43: 563-569).
Figure 1. Protein concentration was quantified in the medium aqueous phase after peanut (A) and rice (B) homogenization in saline buffer (green bars) versus ddH2O (blue bars) using 4 different lysing matrices.
Protein extraction efficiency in peanuts and rice was compared after bead-beating with 4 different lysing kits. The use of saline buffer increased protein extraction efficiency as expected (Robert LS, Nozzolillo C, Altosaar I. Homology between legumin-like polypeptides from cereals and pea. Biochem J 1985; 226: 847-852). The CK14 beads gave the best protein yields compared to the other lysing beads for both hard and soft seeds.