Protein extraction methods utilized in this study and nuclear proteins identified in the various fractions. (A) Suspension cell nuclei and protoplast nuclei were extracted with phenol alone, phenol and 0.4 N sulfuric acid (A & P), and 0.4 N sulfuric acid alone, respectively, followed by subsequent mass analysis. (B) Color-scheme Venn diagrams revealing identified nuclear proteins in each extraction procedure and the overlap among extraction procedures in suspension cell and protoplast nuclear samples. The numbers in circle areas equal the protein number identified. Purple: Acid extraction; Green: Phenol Extraction; Blue: Phenol-Acid double extraction.