Knockdown of Carbonic Anhydrase II was achieved by transfecting A-431 cells with Carbonic Anhydrase II specific siRNAs (Silencer® select Product # s2249, s2248). Western blot analysis (Fig. a) was performed using membrane enriched extracts from the Carbonic Anhydrase II knockdown cells (lane 3), non-specific scrambled siRNA transfected cells (lane 2) and untransfected cells (lane 1). The blots were probed with Anti-Carbonic Anhydrase II Polyclonal Antibody (Product # PA5-33167, 1:1000 dilution) and Rabbit anti-Sheep IgG (H+L) Secondary Antibody, HRP (Product # 61-8620, 0.25  µg/mL, 1:4000 dilution). Densitometric analysis of this western blot is shown in histogram (Fig. b). Decrease in signal upon siRNA mediated knock down confirms that antibody is specific to Carbonic Anhydrase II.