TRYPSIN INHIBITION BY FREE FATTY-ACIDS AND STEAROYL-COA

Potassium salts of long-chain fatty acids inhibited trypsin. The longer the chain, the stronger the inhibition. Among the C18fatty acids, oleate was the most effective inhibitor. Stearoyl-CoA was 25 times more effective in inhibiting trypsin than stearate. Trypsin inhibition by fatty acids was partial and time and temperature dependent. Moreover, the inhibition was found to be a function of the ionization state (solution pH) of the inhibitory compounds. The presence of Ca2+during preincubation of the inhibitor with trypsin protected the enzyme from inhibition. Inhibition appeared to be due to direct binding of the ionized fatty acid monomer to the enzyme rather than to a detergent effect of the inhibitory compounds. © 1990, American Chemical Society. All rights reserved.