Characterisation of the interaction of lactate dehydrogenase with Tween-20 using isothermal titration calorimetry, interfacial rheometry and surface tension measurements.
In this study the nature of the interaction between Tween-20 and lactate dehydrogenase (LDH) was investigated using isothermal titration calorimetry (ITC). In addition the effects of the protein and surfactant on the interfacial properties were followed with interfacial rheology and surface tension measurements in order to understand the mechanism by which the surfactant prevents protein adsorption to the air-water interface. Comparisons were made with Tween-40 and Tween-80 in order to further investigate the mechanism. ITC measurements indicated a weak, probably hydrophobic, interaction between Tween-20 and LDH. Prevention of LDH adsorption to the air-water interface by the Tween surfactants was correlated with surface energy rather than surfactant CMC. While surface pressure appears to be the main driving force for the displacement of LDH from the air-water interface by Tween-20 a solubilisation mechanism may exist for other protein molecules. More generally the results of this study highlight the value of the use of ITC and interfacial measurements in characterising the surface behaviour of mixed surfactant and protein systems.
McAuley
William J
WJ
The School of Pharmacy, The Queen's University of Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK.
Jones
David S
DS
Kett
Vicky L
VL
D002151:Calorimetry / Q000379:methods*; D004347:Drug Interactions / Q000502:physiology; D007770:L-Lactate Dehydrogenase / Q000032:analysis / Q000378:metabolism*; D011136:Polysorbates / Q000032:analysis / Q000378:metabolism*; D012212:Rheology / Q000379:methods; D013500:Surface Tension; D013501:Surface-Active Agents / Q000032:analysis / Q000378:metabolism*; D017186:Titrimetry / Q000379:methods
D011136:Polysorbates; D013501:Surface-Active Agents; D007770:L-Lactate Dehydrogenase