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Activation of CALB by alkylammonium ions: exploring structure activity relationships

Activity: Talk or presentationInvited talk

Description

Candida antarctica lipase B (CALB) is widely used in biocatalysis with applications in plastics
degradation and chemical synthesis. CALB is activated by hydrophobic matrices and shows
striking activation in polar, choline-based, Deep Eutectic Solvents (DES). CALB activation and
stabilisation by tetraalkylammonium (TAA) is caused by binding to choline’s TAA moiety.
Several related TAA salts also caused CALB activation which was proportional to the
hydrophobicity of their alkyl substituents. Notably, tetraoctylammonium bromide showed
activation of ~500% even at low micromolar levels. These TAA salts represent a new class of
enzyme activator. Molecular modelling identified the possible alkylammonium binding location
as a hydrophobic patch centred around Asp-145 of CALB and binding at this site could explain
lipase activation in polar DES solvents.
CALB, like many lipases, is activated by calcium. Intriguingly, mixed soluble activator
experiments showed that calcium and choline bind to different CALB sites, suggesting a twosite model for CALB activation. These observations, along with previous findings, show that
TAA activation is a wider property of enzymes and constitutes a novel and potent means to
enhance enzyme turnover and stability
Period17 Apr 2026
Event titleCozyme COST action working group meeting
Event typeConference
LocationBelgrade, SerbiaShow on map