Effect of salts and sodium dodecyl sulfate on chaperone activity of camel alphaS(1)-CN: insulin as the target protein

Colloids Surf B Biointerfaces. 2009 Jul 1;71(2):300-5. doi: 10.1016/j.colsurfb.2009.03.008. Epub 2009 Mar 25.

Abstract

In this study camel alphaS(1)-casein (alphaS(1)-CN) was purified, using a two-step purification procedure. The anti-aggregation (chaperone-like) ability of the purified protein sample was examined in a wide range of experimental conditions and at different concentrations of camel alphaS(1)-CN, in the presence of salts and sodium dodecyl sulfate (SDS). To examine chaperone-like activity of camel alphaS(1)-CN, bovine pancreatic insulin was used as the target protein. Insulin aggregation performed chemically in the presence of 20 mM dithiotreitol (DTT) and was studied at 360 nm wavelength by UV-vis spectrophotometer. Camel alphaS(1)-CN exhibited a dose-dependent chaperone-like activity as the molar ratios of chaperone/target protein varied between 0 and 0.07. The presence of salts or surfactants changing the protein properties had an influence on chaperone capacity of camel alphaS(1)-CN. The results of UV-visible and fluorimetric measurements indicated that the salts neutralize the chaperone-like activity of casein due to dehydration effect and the increased association and aggregation of proteins, while SDS plays a role as chaperone and chaperone-like properties of camel alphaS(1)-CN enhanced in the presence of SDS due to the binding of the hydrophobic tail of SDS and alphaS(1)-CN to the exposed hydrophobic sites of insulin strongly preventing aggregation of insulin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anilino Naphthalenesulfonates / metabolism
  • Animals
  • Camelus / metabolism*
  • Caseins / metabolism*
  • Cattle
  • Dithiothreitol / pharmacology
  • Fluorescence
  • Hydrophobic and Hydrophilic Interactions
  • Insulin / chemistry
  • Insulin / metabolism*
  • Molecular Chaperones / metabolism*
  • Protein Structure, Quaternary
  • Salts / pharmacology*
  • Sodium Dodecyl Sulfate / pharmacology*

Substances

  • 8-anilino-1-naphthalenesulfonic acid
  • Anilino Naphthalenesulfonates
  • Caseins
  • Insulin
  • Molecular Chaperones
  • Salts
  • Sodium Dodecyl Sulfate
  • Dithiothreitol