The use of the laser light scattering for the molecular weight determination of membrane proteins in surfactants.

: A method is described for the determination of the molecular weight of the protein moiety of protein surfactant complexes using of low angle laser light (633 nm) scattering in combination with high performance porous silica gel chromatography, precision differential refractometry and differential UV absorption was described. The calibration curves in sodium dodecyl sulfate (SDS) and in a non-ionic surfactant, octaethyleneglycol dodecyl ether, using several reference proteins yielded linear lines. Molecular weight of porin oligomers and monomers, an intrinsic membrance protein that forms the permeability channel in the outer membrane of Escherichia coli, were calculated and were found to be 109,000 and 36,300, respectively in SDS and that of oligomers in octaethy leneglycol dodecyl ether was 114,200. Similarly, the molecular weights of maltoporin oligomers and monomers, which form maltose-maltodextrin specific channels, appeared to be 148,500 and 48,200, respectively, in SDS and that of oligomers in octaethyleneglycol dodeclyl ether was 149,000.