R. Jelinek et al., INTERFACIAL CATALYSIS BY PHOSPHOLIPASES AT CONJUGATED LIPID VESICLES - COLORIMETRIC DETECTION AND NMR-SPECTROSCOPY, Chemistry & biology, 5(11), 1998, pp. 619-629
Background: Self-assembled conjugated polymers are rapidly finding bio
logical and biotechnological applications. This work describes a synth
etic membrane system based on self-assembled polydiacetylenes, which a
re responsive to the enzymatic activity of phospholipases - a ubiquito
us class of enzymes that catalyze the hydrolysis of phospholipid molec
ules embedded in cell membranes. Results: We show that phospholipases
are active at bilayer vesicles composed of the natural enzyme substrat
e, dimyristoylphosphatidylcholine (DMPC), and a synthetic pi-conjugate
d polymerized lipid based on polydiacetylene (PDA). In addition, the e
nzymatic reaction induces an optical transition in the surrounding PDA
matrix, visible to the naked eye. Nuclear magnetic resonance spectros
copy confirms the occurrence of enzymatic catalysis and reveals the fa
te of the cleavage products. Conclusions: The results indicate that th
e structural and color changes of the PDA matrix are directly related
to interfacial catalysis by phospholipase. This novel biocatalytic met
hod of inducing optical transitions in conjugated polymers might lead
to new approaches towards rapidly screening new enzyme inhibitor compo
unds.