Aggregation, dissociation and denaturation of sesame (Sesamum indicum L)L-globulin in cetyl trimethyl ammonium bromide solution.

The behaviour of the major protein of sesame seed (Sesamum indicum L.) alpha-globulin
has been studied in a cationic detergent, cetyl trimethyl ammonium
bromide solution. Up to a critical detergent concentration the protein is precipitated
from solution, above which redissolution of the protein is observed.
Sedimentation velocity patterns indicate the presence of higher aggregates in the
detergent concentration range 5 x 10-5 -1 X 10-3 M. These are considered to
be the soluble precursors of the insoluble aggregates. Fluorescence measurements
show that tryptophanyl groups of the protein which are in contact with the
aqueous phase are perturbed by the detergent. The difference spectra of the
protein in higher concentration of detergent indicate considerable red shift in
the spectrum. Spectrophotometric titration of phenolic groups in 1 X 10-2 M
eTAB indicate that a conformational change in the protein has taken place.