Studies on the mechanism of crown-ether-induced activation of enzymes in non-aqueous media.

Studies on the mechanism of crown-ether-induced activation are described in this paper. Michaelis Menten kinetics of α-chymotrypsin in toluene in the presence and absence of 18-crown-6 showed that only Vmax is increased upon crown ether treatment. Parallel Lineweaver–Burk plots indicate that crown ethers do not activate the enzyme by specific interactions in the active site, such as transition state stabilization or facilitated transport of water molecules. Increased Vmax values of crown-ether-treated enzyme most probably originate from conformational changes, which alter kcat as well as the amount of catalytically active enzyme.