The interaction of vitamin K1 with phospholipid membranes

The effects of vitamin K1 (VK) on dipalmitoylphosphatidylcholine (DPPC) membrane were studied by surface monolayer, differential scanning calorimetry and fluorescence techniques. DPPC and VK are proved to be freely miscible in the mixed monolayer at an air/water interface, and to be partially miscible in bulk phase, i.e. bilayer and solid phase. There is a condensing interaction between VK and DPPC in the VK/DPPC mixed monolayers. The solubility of VK in the DPPC is about 20 mol% and the solubility of DPPC in VK is about 10 mol%. The membrane fluidity of DPPC was increased by the addition of VK and the phase transition temperature was decreased.