Enzymatic Reaction in a Vesicular Microreactor: Peptaibol‐Facilitated Substrate Transport

Abstract

Catalytic reactions performed with enzymes localized in lipid vesicles or in whole cells represent a new, promising approach in biocatalysis. The delivery of different substrates into these micro- or nano-'reactors' requires a sufficient permeability of lipid membranes. To increase the permeability of lipid bilayers, one may use different membrane-active peptides, including peptaibols. In the present study, the trypsin-catalyzed hydrolysis of N(alpha)-benzoyl-L-arginine-para-nitroanilide (BAPA; 1) was studied in a phospholipid vesicular system made of phosphatidylcholine (POC), in the presence of the peptaibols alamethicin (ALM) or zervamicin IIB (ZER). Two different manners of compartmentalization of substrate and enzyme (enzyme- vs. substrate-containing vesicles) were used. The kinetics parameters of the reaction in homogeneous solution and in the vesicular systems were determined. The rate of the extra- or intravesicular enzymatic reaction was found to be controlled by substrate diffusion through the lipid bilayer. In comparison with untreated vesicular systems, an up to seven-fold increase in reaction rate was observed in the presence of either ALM or ZER.

Recent Results in Alamethicin Research

“…Kropacheva and Raap [38] reported the biotechnological application of ALM-membrane system for improving the bilayer-separated enzyme reactions using a new strategy for increasing the substrate permeability through membrane bilayers.…”

Alamethicin Supramolecular Organization in Lipid Membranes from 19F Solid-State NMR

“…These observations show that Gln 7 (and also Gly 11 and Pro 14 ) are not absolutely required for ion channel formation. Finally, it is worthwhile to mention that at high concentrations of ALM and independently of transmembrane potentials, bulky ions (e.g., N a -benzoyl-L-argininepara-nitroanilide and carboxyfluorescein) are able to pass the membrane (19)(20)(21).…”

Influences of the concentration and the molar ratio of mixed surfactants on the performance of vesicle pseudostationary phase

“…After that, the researchers had obtained the vesicles that were formed spontaneously from many mixed systems, such as amphoteric and anionic surfactants, nonionic surfactant and cosurfactant, and anionic and cationic surfactants. Because of the special properties and structures, the vesicles play a great role in the fields of capillary electrokinetic chromatography , biological simulation , drug encapsulation and targeted release , microreactor , capillary LC , and open‐tubular CEC .…”