In Vitro Stimulation by Retinol of Porcine Pancreatic Esterase Activity toward Esters of Short-chain Fatty Acids

Abstract

1. Retinol exerted a remarkable stimulating effect (approx. 260% increase), essentially similar to that (300%) of phytol, on the so-called esterase activity displayed by crude pancreatic lipase [EC 3.1.1.3] toward true solutions of esters, but none of the typical lipase activity toward emulsions of water-insoluble esters. 2. Comparison of the stimulatory effects of retinol derivatives on the esterase activity revealed that retinyl acetate was the most active, being sustantially similar in effect to retinol; retinal was fairly active, while retinoic acid, retinyl palmitate, and beta-ionone were far less active. 3. With various isoprenoid compounds, the efficiency of stimulation increased with the carbon chain length, attaining a maximum at 15 to 20 carbon atoms. Above this chain length the efficiency decreased rapidly. 4. Comparison of the effects of retinol and phytol on the esterase activity of various other lipolytic enzymes indicated that this kind of activator may be relatively specific to porcine pancreatic esterase activity.

Effect of Unsaponifiable Lipid Components from the Red AlgaPorphyra teneraon Pancreatic Carboxylesterase Activity toward TriacetinIn Vitro

“…We have thus far studied the isolation and characterization of the activator, which stimulates markedly the hydrolysis of triacetin (TAesterase activity) by a porcine pancreatic lipase preparation, from the marine brown alga Hizikia fusiformis (hiziki).l -8) It has been found that phytol 6 ) isolated from hiziki is a typical activator of this kind, and recently that parathion 9 ) as well as retinol 10 ) exhibits a remarkable stimulating action, essentially similar to that observed with phytol, on the TAesterase activity.…”