WB; Western Blotting (WB). A concentration of 2.0-4.0 µg/mL is recommended for cells and tissues. Human Spectrin alpha chain (isoform 1) has a predicted length of 2,419 residues and a MW of 280 kDa. Human Spectrin beta chain (isoform 1) has a predicted length of 2,137 residues and a MW of 246 kDa.