POPSO is a zwitterionic buffer, increases osmolality and shows marked inhibition of anion uniport. POPSO inhibits chloride uniport with an IC50 value of 24 mM. POPSO enhances copper uptake and toxicity in alga, impairs mitochondrial inner membrane. The working pH range of POPSO sesquisodium salt is 7.2-8.5[1][2][3].
[1]. Ng LT, et al. Effect of buffers and osmolality on anion uniport across the mitochondrial inner membrane. Biochim Biophys Acta. 1993 Jun 10;1143(1):29-37.
[2]. Vasconcelos, et al. Influence of zwitterionic pH buffers on the bioavailability and toxicity of copper to the alga Amphidinium carterae. 2009 Nov;19(10):2542-2550.
[3]. Kebede N, et al. Electrogenerated chemiluminescence of tris(2,2' bipyridine)ruthenium(II) using common biological buffers as co-reactant, pH buffer and supporting electrolyte. Analyst. 2015 Nov 7;140(21):7142-5.