Abstract
To clarify the mechanism of a possible fatty acid (FA)-induced inhibition of pseudocholinesterase (pchE, EC 3. 1. 1. 8), the interaction or binding of pchE with FA was studied lusing ultrafiltration and dialysis techniques and circular dichroism and ultraviolet spectrometries. The binding study showed that pchE activity was inhibited by FA's (capric acid or lauric acid) containing 10 or 12 carbon atoms, which bind to the pchE molecule, but not by FA's (caproic acid and caprylic acid) which do not bind with pchE. Dialysis of pchE solution with lauric acid containing [1-14C] lauric acid showed the irreversibility of both lauric acid binding to the pchE molecule and lauric acid-induced inhibition of pchE activity. Circular dichroism and ultraviolet spectra of pchE shifted in proportion to the concentration of capric acid added, suggesting a conformational change in the pchE molecule. The present study indicated that FA-induced inhibition of pchE is based on the irreversible interaction or binding of pchE with FA.
