Interaction of 3-O-caffeoyl D-quinic acid with multisubunit protein helianthinin.
IR@CFTRI: CSIR-Central Food Technological Research Institute, Mysore
View Archive Info| Field | Value | |
| Relation |
http://ir.cftri.com/4487/
|
|
| Title |
Interaction of 3-O-caffeoyl D-quinic acid with multisubunit protein helianthinin.
|
|
| Creator |
Suryaprakash, P.
Prakash, V. |
|
| Subject |
03 Proteins
Sunflower Seed |
|
| Description |
Chlorogenic acid, 3’-O-caffeoyl D-quinic acid, is an inherent ligand present in
Helianthus annuus L. The effect of pH on chlorogenic acid binding to helianthinin suggests
that maximum binding occurs at pH 6·0. The protein-polyphenol complex precipitates as a
function of time. The association constant of the binding of chlorogenic acid to helianthinin,
determined by equilibrium dialysis, at 31°C has a value of 3·5 ± 0·1 × 104M–1 resulting in a
ΔG value of – 6·32 ±0·12 kcal /mol. The association constant Ka is 1·0 ± 0·1 × 104M-1 as
determined by ultraviolet difference spectral titration at 25°C with ΔGo of -5·46 ± 0·06 kcal/mol.
From fluorescence spectral titration at 28°C, the Ka value is 1·38 ± 0·1 × 1 0 4M-1 resulting
in a ΔG of – 5·70 ± 0·05 kcal/mol. The total number of binding sites on the protein are
420 ± 50 as calculated from equilibrium dialysis. Microcalorimetric data of the ligand-protein
interaction at 23°C suggests mainly two classes of binding. The thermal denaturation
temperature, Tm of the protein decreases from 76°C to 72°C at 1 × 10-3M chlorogenic acid
concentration upon complexation. This suggests that the complexation destabilizes the
protein. The effect of temperature on Ka of chlorogenic acid shows a nonlinear increase
from 10·2°C to 45°C. Chemical modification of both lysyl and tryptophanyl residues of
the protein decreases the strength of binding of chlorogenic acid. Lysine, tryptophan and
tyrosine of protein are shown to be present at the binding site. Based on the above data,
it is suggested that charge-transfer complexation and entropically driven hydrophobic
interaction are the predominant forces that are responsible for binding of chlorogenic acid
to the multisubunit protein, helianthinin.
|
|
| Date |
1995
|
|
| Type |
Article
PeerReviewed |
|
| Format |
pdf
|
|
| Language |
en
|
|
| Identifier |
http://ir.cftri.com/4487/1/J.%20Biosci.%2C%20Vol.%2020%2C%20Number%204%2C%20September%201995%2C%20pp%20531%E2%80%93549-1.pdf
Suryaprakash, P. and Prakash, V. (1995) Interaction of 3-O-caffeoyl D-quinic acid with multisubunit protein helianthinin. Journal of Biosciences, 20 (4). pp. 531-549. |
|