MEGA-8

MEGA-8 is a nonionic glucoside surfactant obtained by condensation of octanoyl (C8 straight-chain acyl) group with N-methylglucamine^[1]. MEGA-8 is characterized by its mildness and non-denaturing nature, with a critical micelle concentration (CMC) that is virtually unaffected by temperature in the range of 5–40 °C, and its CMC is 70 mM in salt-free conditions and 5–64 mM under high- and low-salt conditions^[2][3]. MEGA-8 is usually used in the preparation of biomaterials or organic compounds and is commonly found in life science research, such as protein extraction and membrane protein solubilization^[4][5]. When combined with CHAPS, MEGA-8 synergistically reduces the CMC and enhances surface activity, thereby efficiently solubilizing membrane proteins under mild conditions^[6]. MEGA-8 gently displaces PrBP/δ and inhibits the basal activity of PDE6 while maintaining the integrity and homogeneity of the holoenzyme complex, thus providing an ideal detergent environment for the purification and structural studies of retinal phosphodiesterase 6^[7].

References:
[1] Jeffrey GA, Maluszynska H. The structures of 1-deoxy-(N-methyloctanamido)-D-glucitol (MEGA-8) and 1-deoxy-(N-methylundecanamido)-D-glucitol (MEGA-11). Acta Crystallogr B. 1989;45 ( Pt 4):447-452.
[2] Walter A, Suchy SE, Vinson PK. Solubility properties of the alkylmethylglucamide surfactants. Biochim Biophys Acta. 1990;1029(1):67-74.
[3] Miyagishi S, Okada K, Asakawa T. Salt Effect on Critical Micelle Concentrations of Nonionic Surfactants, N-Acyl-N-methylglucamides (MEGA-n). J Colloid Interface Sci. 2001;238(1):91-95.
[4] Luescher IF, Unanue ER. Purification and photoaffinity labeling of the I-Ak histocompatibility molecule. J Immunol Methods. 1990;135(1-2):233-245.
[5] Banerjee P, Joo JB, Buse JT, Dawson G. Differential solubilization of lipids along with membrane proteins by different classes of detergents. Chem Phys Lipids. 1995;77(1):65-78.
[6] Ko JS, Oh SW, Kim KW, Nakashima N, Nagadome S, Sugihara G. Blending effects on adsorption and micellization of different membrane protein solubilizers: a thermodynamic study on three mixed systems of CHAPS with MEGA-8, -9 and -10 in pH 7.2 phosphate buffer solution. Colloids Surf B Biointerfaces. 2005;45(2):90-103.
[7] Baker BY, Palczewski K. Detergents stabilize the conformation of phosphodiesterase 6. Biochemistry. 2011;50(44):9520-9531.

MEGA-8是辛酰基（C8直链酰基）与N-甲基葡糖胺缩合得到的非离子型糖基表面活性剂^[1]。MEGA-8具有温和、非变性的特点, 临界胶束浓度（CMC）在5–40°C 范围内几乎不受温度影响，在无盐条件下的CMC为70mM，高盐和低盐条件下的临界胶束浓度（CMC）为5–64mM^[2][3]。MEGA-8主要用于生物材料或有机化合物的制备，常见于生命科学相关研究中，如蛋白提取、膜蛋白溶解等^[4][5]。MEGA-8与CHAPS复配后，通过协同作用显著降低临界胶束浓度并提高表面活性，从而在温和条件下高效增溶膜蛋白^[6]。MEGA-8温和地取代PrBP/δ并抑制PDE6的基底活性，同时保持全酶复合物的完整性和均匀性，从而为视网膜磷酸二酯酶6的纯化和结构研究提供了理想的净化环境^[7]。