Premium
Effect of pH and Ionic Strength on the Heat Stability of Rapeseed 12S Globulin (Cruciferin) by the ANS Fluorescence Method
Author(s) -
Folawiyo Yetunde L,
Apenten Richard K Owusu
Publication year - 1996
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/(sici)1097-0010(199602)70:2<241::aid-jsfa490>3.0.co;2-h
Subject(s) - chemistry , ionic strength , rapeseed , fluorescence , sodium , chromatography , heat stability , heat sensitive , globulin , globular protein , analytical chemistry (journal) , biochemistry , food science , materials science , aqueous solution , physics , organic chemistry , layer (electronics) , quantum mechanics , immunology , composite material , biology
The heat stability of rapeseed 12S globulin (cruciferin) was examined using 8‐anilinonaphthalene‐1‐sulphonic acid (ANS) as a fluorescence probe. Heating cruciferin (0·06–0·3 mg ml −1 in 10 mM glycyl–glycyl piperizine buffer, pH 7·0, with 0·1–1·0 M NaCl) for 20 min increased its hydrophobicity as monitored by ANS fluorescence measurements. The mid‐point temperature for the heat effect (T m ) increased linearly with increasing solvent pH (T m (°C)=4·16 pH+41 (μ=0.1)) or sodium chloride concentration (T m (°C)=14·7 [NaCl]+71 (pH=7·0)). The range of T m values for cruciferin was 45–96°C. At 20°C cruciferin was unstable at pH<3·0 but relatively stable under alkaline conditions (pH 8–10). Though possessing an oligomeric structure, cruciferin appears to heat denature in accordance with the two‐stage deactivation model for simple globular proteins.