Styrene - maleic acid (SMA) copolymers are broadly used for function and structure studies of membrane proteins. The significant advantages of using SMA copolymers include (1) generating a detergent-free system and (2) forming bilayer nanodiscs with phospholipids. Application of SMA copolymers opens an avenue of membrane protein extraction from cell membranes and proteoliposomes in the absence of detergent. The extracted membrane proteins are stabilized in the nanodiscs that mimic the bilayer structure of lipids in nature. The membrane proteins in nanodiscs can be purified and employed in biochemical, biophysical and biological experiments. For example, the nanodiscs can be used for structure studies of membrane proteins by electronic microscopy (EM). Typically SMA copolymers 2:1 forms nanodiscs in a size about 30 nm while SMA copolymers 3:1 forms nanodiscs in a size about 10 nm.  The ideal pH for nanodisc formation is between pH 7.0 – 8.0.

Styrene - Maleic Acid Copolymer 2:1 Free Acid is the free acid form of SMA Copolymer with a molar ratio of styrene to maleic acid of 2:1. The copolymer molecular weight is 10.1 kDa. The free acid form of SMA copolymer is soluble in a pH 8.5 buffer. The package size is 100 mg, 500 mg, 5000 mg and 25 g.

Styrene - Maleic Acid Copolymer 2:1 Sodium Salt is the sodium salt form of SMA copolymer with a molar ratio of styrene to maleic acid of 2:1.  The copolymer molecular weight is 10.4 kDa.  The salt form of SMA copolymer is soluble in pure water. The package size is 100 mg, 500 mg, 5000 mg and 25 g.

Styrene - Maleic Acid Copolymer 2:1 Solution, pH 7.6 – 10 ml (Catalog No. SMA21-10ML) includes 10 ml of 5% Styrene - Maleic Acid Copolymer 2:1 in 0.1 M Tris-HCl, pH 7.6.

For information of Styrene – Maleic Acid 3:1 Copolymer free acid and salt, please click here.