Plant-based foods as a source of lipotropes for human nutrition: a survey of in vivo studies.
Nicotinic acid and nicotinamide inhibit in vitro the acetyl-CoA-carboxylase activity of partially purified enzyme from chicken liver. The incorporation of 10, 20, 50 and 100 mkmoles of nicotinic acid or nicotinamide into the incubation medium (0,9 ml) leads to the inhibition of the enzyme activity by 19, 45, 70 and 100% and by 39, 51, 60 and 78%, respectively. NADH+ and NADP+ at concentrations by one order of magnitude lower than those of nicotinic acid and nicotinamide decrease the enzyme activity in a similar manner. The constants of inhibition by the above-mentioned compounds were calculated with respect to ATP, acetyl-CoA and citrate.