Propionate, a source of β-alanine, is an inhibitor of β-alanine methylation in Limonium latifolium, Plumbaginaceae

The origin of β-alanine was investigated in Limonium latifolium (Plumbaginaceae), an angiosperm species that methylates β-alanine to β-alanine betaine, an osmoprotective compound. The hypothesis that propionate metabolism leads to β-alanine in L. latifolium was tested using radiotracer labeling techniques. 2-[14C]-Propionate was supplied to leaf and root tissues. Following incubation for defined periods, radiolabel was identified in β-alanine. However, in both the tissues, little radioactivity was found in the methylated derivatives of β-alanine namely N-methyl β-alanine, N,N-dimethyl β-alanine and β-alanine betaine, suggesting that propionate was inhibitory to β-alanine methylation. This conclusion was confirmed by in vitro assays wherein propionate was found to be highly inhibitory to β-alanine N-methyltransferase activity in a leaf protein fraction.