Development of a Simple and Reproducible Method for Removal of Contaminants from Ginseng Protein Samples Prior to Proteomics Analysis

This study describes the effects of activated charcoal on the removal of salts, detergents, and pigments from protein extracts of ginseng leaves and roots. Incubation of protein extracts with 5% (w/v) activated charcoal (100-400 mesh) for 30 min at 4°C almost removed the salts and detergents including NP-40 as can be observed on SDS-PAGE. In addition, analysis of chlorophyll content showed significant depletion of chlorophyll (~33%) after activated charcoal treatment, suggesting potential effect of activated charcoal on removal of pigments too along with the salts and detergents. 2-DE analysis of activated charcoal treated protein samples showed better resolution of proteins, further indicating the efficacy of activated charcoal in clearing of protein samples. In case of root proteins, although not major differences were observed on SDS-PAGE, 2-DE gels showed better resolution of spots after charcoal treatment. In addition, both Hierarchical clustering (HCL) and Principle component analysis (PCA) clearly separated acetone sample from rest of the samples. Phenol and AC-phenol samples almost overlapped each other suggesting no major differences between these samples. Overall, these results showed that activated charcoal can be used in a simple manner to remove the salts, detergents and pigments from the protein extracts of various plant tissues.