Hydrophobic probe binding of beta-lactoglobulin in the native and molten globule state induced by high pressure as affected by pH, KlO(3) and N-ethylmaleimide

摘要

High hydrostatic pressure (HHP) at 500 MPa and 50 degreesC induces beta-LG into the molten globule state. Retinol, cis-parinaric acid (CPA), and 1-anilino-naphthalene-8-sulfonate (ANS) fluorescence from PH 2.5 to 10.5 in the presence of the native and molten globule states of beta-LG indicate that retinol binds to beta-LG in the calyx, CPA at the surface hydrophobic site, and,ANS in multiple hydrophobic sites. HHP treatment results in a decrease of beta-LG affinity for retinol and CPA, suggesting conformational changes in the calyx and surface hydrophobic site of beta-LG,during,HHP treatment. beta-LG treated by HHP in the presence of N-ethylmaleimide (NEM) retains retinol affinity,suggesting that NEM protects the calyx conformation of 0,,beta-LG during HHP treatment., HHP treatment of beta-LG in the,presence of K10(3) exhibits a great decrease of CPA affinity, compared, to. HHP-treated beta-LG in the absence of K103, suggesting the formation of non-native disulfide, bonding at them CPA binding site.