Enzymatic reactions in liposomes using the detergent-induced liposome loading method.
Microcompartmentalization is a crucial step in the origin of life. More than 30 years ago, Oparin et al. proposed models based on biochemical reactions taking place in so-called coacervates. Their intention was to develop systems with which semipermeable microcompartments could be established. In the present work we follow their intuition, but we use well-characterized bilayer structures instead of the poorly characterized coacervates. Liposomes from phospholipids can be used as microreactors but they exhibit only a modest permeability and, therefore, chemical reactions occurring inside these structures are depleted after a relatively short period. Here it is shown that even highly stable liposomes from 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) can be used as semipermeable microreactors when treated with sodium cholate. Using this kind of mixed liposomes, we describe a biochemical reaction occurring inside the liposomes while the same reaction is prevented in the external medium. In addition, we show that this cholate-induced permeability of POPC bilayers can even be used to load macromolecules such as enzymes from the outside.
Oberholzer
T
T
Institut für Polymere, ETH Zentrum, Universitätsstrasse 6, CH-8092, Zürich, Switzerland.
Meyer
E
E
Amato
I
I
Lustig
A
A
Monnard
P A
PA
D020355:Cholates; D003850:Deoxyribonuclease I / Q000737:chemistry; D003902:Detergents; D006003:Glycogen / Q000138:chemical synthesis; D008081:Liposomes / Q000737:chemistry*; D046911:Macromolecular Substances; D008722:Methods; D010539:Permeability; D010713:Phosphatidylcholines; D006005:Phosphorylases / Q000737:chemistry
D020355:Cholates; D003902:Detergents; D008081:Liposomes; D046911:Macromolecular Substances; D010713:Phosphatidylcholines; D006003:Glycogen; D006005:Phosphorylases; D003850:Deoxyribonuclease I; C028694:1-palmitoyl-2-oleoylphosphatidylcholine