Fonterra Research Centre, Private Bag 11029, Palmerston North, New Zealand.
Biomacromolecules. 2011 Nov 14;12(11):3970-6. doi: 10.1021/bm200978k. Epub 2011 Oct 7.
On addition of lactoferrin (LF) to skim milk, the turbidity decreases. The basic protein binds to the caseins in the casein micelles, which is then followed by a (partial) disintegration of the casein micelles. The amount of LF initially binding to casein micelles follows a Langmuir adsorption isotherm. The kinetics of the binding of LF could be described by first-order kinetics and similarly the disintegration kinetics. The disintegration was, however, about 10 times slower than the initial adsorption, which allowed investigating both phenomena. Kinetic data were also obtained from turbidity measurements, and all data could be described with one equation. The disintegration of the casein micelles was further characterized by an activation energy of 52 kJ/mol. The initial increase in hydrodynamic size of the casein micelles could be accounted for by assuming that it would go as the cube root of the mass using the adsorption and disintegration kinetics as determined from gel electrophoresis. The results show that LF binds to casein micelles and that subsequently the casein micelles partly disintegrate. All micelles behave in a similar manner as average particle size decreases. Lysozyme also bound to the casein micelles, and this binding followed a Langmuir adsorption isotherm. However, lysozyme did not cause the disintegration of the casein micelles.
在脱脂乳中添加乳铁蛋白（LF）后，浊度降低。碱性蛋白与酪蛋白胶束中的酪蛋白结合，随后酪蛋白胶束发生（部分）解体。最初与酪蛋白胶束结合的 LF 量遵循朗缪尔吸附等温线。LF 的结合动力学可以用一级动力学来描述，类似地，解体动力学也可以用一级动力学来描述。然而，解体速度比初始吸附速度慢约 10 倍，这使得两种现象都可以进行研究。通过浊度测量也获得了动力学数据，所有数据都可以用一个方程来描述。通过动力学数据进一步确定了酪蛋白胶束的解体活化能为 52kJ/mol。假设根据凝胶电泳确定的吸附和解体动力学，将其作为质量的立方根，那么可以解释酪蛋白胶束的水动力粒径的初始增加。结果表明 LF 与酪蛋白胶束结合，随后酪蛋白胶束部分解体。所有胶束的行为都相似，因为平均粒径减小。溶菌酶也与酪蛋白胶束结合，这种结合遵循朗缪尔吸附等温线。然而，溶菌酶不会导致酪蛋白胶束解体。
