The Effect of Heat Treatment on Anilinonaphthalene-8-Sulphonate Binding to Rapeseed Albumin (Napin)
✍ Scribed by Nyman, Rachel; Apenten, Richard K Owusu
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 189 KB
- Volume
- 74
- Category
- Article
- ISSN
- 0022-5142
No coin nor oath required. For personal study only.
✦ Synopsis
Protein surface hydrophobicity can be measured by the Ñuorescent probe method. The e †ect of heat treatment on Brassica napus (rapeseed) albumin (napin) interactions with a Ñuorescent probe, anilinonaphthalene-8-sulphonic acid (ANS) was investigated by Ñuorescent titration. Upon heating to 100¡C for 30 min the number of napin binding sites for ANS (n) increased from 5(^0É7) to 13(^0É5) moles of ANS bound per mole of protein. The ANS-protein dissociation constant (Kd) was 2É0(^0É4) ] 10~6 M for the unheated protein and 10É4(^0É1) ] 10~6 M for heat-denatured napin. There was also a blue shift in the Ñuorescence emission spectrum maximum for denatured napinÈANS complex consistent with an increase in the hydrophobicity of the ANS binding sites in the denatured protein. The characteristic Ñuorescence increase for heat-denatured albuminÈANS mixtures is therefore due to an increase in the number, binding affinity and hydrophobicity of binding sites. Heat treatment of napin leads to the appearance of additional surface hydrophobic sites in the denatured protein.