Lag phase and hydrolysis mechanisms of triacylglycerol film lipolysis.
We here present novel insights into the dynamic changes of a nanosized lipid film during enzymatic degradation. When adding an aqueous solution containing a triacylglycerol lipase to an approximately 100nm thin triolein film, which is supported on a hard surface, the film thickness, elasticity, viscosity, and chemical composition were obtained continuously. Both a mechanical technique (quartz crystal microbalance with dissipation monitoring) and a spectroscopic technique (attenuated total reflection Fourier transform infrared spectroscopy) were utilised for this study. Detailed data revealed the effects of pH, Ca(2+), and catalytic rate on lipolysis, including product release from the film. It was found that under basic conditions and without Ca(2+), the lipolytic activity commence instantaneously upon addition of enzyme, whereas product release from the substrate film awaits conditions that favours release. A model for removal of degradation products from the film is introduced, including a novel interpretation of the lag phase phenomenon.
Snabe
Torben
T
Section of Biostructure and Protein Engineering, Institute of Life Sciences, Aalborg University, DK-9000, Aalborg, Denmark.
Petersen
Steffen Bjørn
SB
D004548:Elasticity; D006868:Hydrolysis; D008049:Lipase / Q000378:metabolism*; D008066:Lipolysis; D017550:Spectroscopy, Fourier Transform Infrared; D014280:Triglycerides / Q000737:chemistry / Q000378:metabolism*; D014304:Triolein / Q000737:chemistry / Q000378:metabolism*; D014783:Viscosity
D014280:Triglycerides; D014304:Triolein; D008049:Lipase