Kinetics of Thermal Denaturation of β-Lactoglobulin at pH 2.5

摘要: Abstract Thermal denaturation of β-lactoglobulin at pH 2.5 was studied temperatures ranging from 60 to 130C. Changes were followed by measurements specific optical rotation \[ α \] 589 25 and solubility 4.5. Denaturation, as determined both methods, irreversible evident only 75C or above, a higher temperature than 65C reported for neutral pH. Also, the cooperative transition (83 84C) 6.7 (68 69C). in indicated that all above proceeded two stages. The first stage (up 5min) faster subsequent (5 60min). Specific rotations 4.5-insoluble fraction resolubilized 4.5-soluble fraction, readjusted 2.5, increased steadily with duration heat treatment, indicating progressively unfolding protein molecules. Stable not reached after heating 60min. final much lower (∼100) achieved presence concentrated urea guanidine hydrochloride. could be fitted into simple kinetic scheme. extent measured loss 4.5 it pseudo first-order consecutive reactions. Denaturation rate constants slope lines. Arrhenius plot logarithm apparent constant function reciprocal (°K) enabled calculation activation energy (∼43 Kcal/mol) heated 2.5. kinetics thermal have been compared those