Sodium #-lauroylsarcosine, or Sarkosyl, is a detergent that is structurally related to SDS, except that Sarkosyl has an additional polar and rigid peptide bond linkage within the hydrophobic backbone (Fig. 1). Such rigidity added to the N-terminus of the hydrophobic chain could lead to a decrease in its ability to be inserted freely into hydrophobic membrane bilayers and proteins. This could explain why Sarkosyl is milder than SDS in its ability to denature and disrupt membrane and protein structures. Because of a similar difference in side-chain structure, the bile acid detergent CHAPS is rendered milder than the strongly denaturing sodium cholate, which inactivates integral membrane proteins, such as the serotonin 1A receptor (1). The relatively mild nature of Sarkosyl has been exploited at least in a few cases. Important examples include the purification of Escherichia coli RNA polymerase sigma factors by solubilizing inclusion bodies (2) and the solubilization and purification of the scrapie protein, the prion PrPSc (3, 4). Although comparison of the structural features of Sarkosyl with those of other detergents suggests that it might be effective in solubilizing functionally active membrane proteins, the major use of Sarkosyl has been to isolate DNA and RNA. The principal reason for this is that Sarkosyl is highly efficient in dissociating nucleosomes and ribosomes (5). The detergent also denatures nucleic acids and inhibits certain enzymes, such as deoxyribonucleases and ribonucleases, which could degrade these molecules.
Figure 1. The structure of Sarkosyl.
