Action of Vipoxin and its separated components on monomolecular film of Dilauroylphosphatidylcholine at the air/water interface

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Vol. 562; pp. 196 - 202
• Main Authors: Mircheva, K., Petrova, S.D., Ivanova, Tz, Panaiotov, I., Balashev, K.T.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.02.2019
• Subjects: Atomic force microscopy (AFM); Enzyme kinetics; Phospholipases A2; Vipoxin; Vipoxin; Atomic force microscopy (AFM); Phospholipases A2; Enzyme kinetics
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2018.11.040

[Display omitted] The growing research interest about neurotoxin Vipoxin is inspired by its intriguing heterodimeric structure and the resulting interactions between Vipoxin’s basic catalytic subunit and the acidic regulatory subunit. In this paper we studied the enzymatic action of Vipoxin and its individual components on Dilauroylphosphatidylcholine (DLPC) monolayers at air-water interfaces. We applied the classical surface barostatic method and interpreted our experimental data with an adapted Michaelis-Menten kinetic model. This approach allowed us to obtain the global kinetic constants together with the interfacial specific activity of Vipoxin and its subunits. Using reconstituted Vipoxin complexes formed by incubating the enzymatic VBC-sPLA2 and non-catalytic VAC subunits in different ratios, we showed that the activity of the reconstituted mixture VAC:VBC-sPLA2 (1:1), which should correspond to the composition of Vipoxin, is higher than that of the natural Vipoxin complex. Finally, Vipoxin heterodimers in the DLPC monolayer were imaged by Atomic force microscope (AFM) and statistically analyzed.