Considering the homology between NOXA1 and theNOX2 activating subunit p67phox, the authors selected aportion of the sequence in which 46% of the amino acids are dissimilarbetween p67phox and NOXA1 in order to obtain NOX1 specificity.In fact, 31 was found to be selective for NOX1 over NOX2,NOX4, and NOX5 as well as inactive against xanthine oxidase and wasused to investigate the role of NOX1 in a different type of hypertension,pulmonary arterial hypertension.250−252. This evidence concerns the gene NCF2 and pulmonary arterial hypertension.