5-hydroxy Isatin is an inhibitor of monoamine oxidase A (MAO-A; IC50 = 8.4 µM).1 It is selective for MAO-A over MAO-B (IC50 = >100 µM). 5-hydroxy Isatin (50 µM) also inhibits atrial natriuretic peptide-induced activation of particulate guanylyl cyclase in rat brain and heart membranes.2
1.Medvedev, A.E., Goodwin, B., Chow, A., et al.Inhibitory potency of some isatin analogues on human monoamine oxidase A and BBiochem. Pharmacol.44(3)590-592(1992) 2.Medvedev, A.E., Goodwin, B.L., Sandler, M., et al.Efficacy of isatin analogues as antagonists of rat brain and heart atrial natriuretic peptide receptors coupled to particulate guanylyl cyclaseBiochem. Pharmacol.57(8)913-915(1999)