Dual behavior of sodium dodecyl sulfate as enhancer or suppressor of insulin aggregation and chaperone-like activity of camel alphaS(1)-casein

Int J Biol Macromol. 2009 Dec 1;45(5):511-7. doi: 10.1016/j.ijbiomac.2009.08.008. Epub 2009 Aug 31.


Sodium dodecyl sulfate (SDS) at low concentrations considerably enhanced insulin aggregation and reduced the chaperone-like activity of purified camel alphaS(1)-casein (alphaS(1)-CN). These observed changes were the result of repulsive electrostatic interactions between both negative charged head groups of SDS and alphaS(1)-CN, and the net negative charge of insulin molecules, resulting in the greater exposure of hydrophobic patches of insulin and its enhanced aggregation. In contrast, enhanced hydrophobic interactions were primarily responsible for the conformational changes observed in insulin and alphaS(1)-CN at high SDS concentrations, resulting in increased binding of SDS and alphaS(1)-CN to insulin and its reduced aggregation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Buffers
  • Camelus
  • Caseins / chemistry*
  • Circular Dichroism
  • Dithiothreitol / chemistry
  • Hydrophobic and Hydrophilic Interactions
  • Insulin / chemistry
  • Insulin / metabolism*
  • Milk / metabolism
  • Molecular Chaperones / chemistry*
  • Protein Binding
  • Sodium Dodecyl Sulfate / chemistry*
  • Static Electricity
  • Time Factors
  • Ultraviolet Rays


  • Buffers
  • Caseins
  • Insulin
  • Molecular Chaperones
  • Sodium Dodecyl Sulfate
  • Dithiothreitol