ADRB2 and asthma: While we have previously demonstrated that H2O2 and β2AR agonism can facilitate transient cysteine-S-sulfenation of the β2AR, a novel and principal finding of our current study is that acute treatment of healthy or asthma-diseased SAEC with the fully efficacious β-agonist ISO or the clinically used and selective β2-partial agonist salbutamol induces formation of higher-order cysteine-S-sulfinic acids of β2AR, as detected by a clickable, selective Cys-S-sulfinic acid probe.