THE CONVERSION OF SHIKIMIC ACID INTO CERTAIN AROMATIC COMPOUNDS BY CELL-FREE EXTRACTS OF AEROBACTER AEROGENES AND ESCHERICHIA COLI

Publisher Website
Google Scholar
Abstract
The conversion of shikimic-acid into anthranilic-acid (a precursor of tryptophan) with crude cell extracts of A. aerogenes T-17 (a tryptophan auxotroph unable to convert anthranilic-acid into indolylglycerol-phosphate was studied. Substrates required for maximum anthranilic-acid production were adenosine-triphosphate (ATP). MgCl2, L.-glutamine, nicotinamide-adenine-dinucleotide (NAD) or NADH2 and a sugar phosphate (ribose 5-phosphate, glucose 6-phosphate or fructose 6-phosphate). Inorganic phosphate and L-tryptophan strongly inhibited anthranilic-acid production. Phosphoeneolpyruvic-acid and excess of ATP were also inhibitory. Shikimic -acid plus ATP could be replaced by shikimic-acid 5-phosphate as a substrate. Requirements for the conversion of shikimic-acid 5-phosphate into anthranilic-acid by (NH4)2 SO4 -precipitated enzyme preparations were phosphoenolpyruvic-acid, NADH2, L-glutamine and phosphorylated sugar. Omission of glutamine or addition of L-tryptophan decreased anthranilic-acid production and stimulated phenylpyruvic-acid and 4-hydroxyphenylpyruvic-acid production. The requirements for the production of the phenylpyruvic-acids by crude extracts from shikimic-acid were MgCl2 ATP, phosphorylated sugar and NAD. Inorganic phosphate was inhibitory. Requirements for the conversion of shikimic acid 5-phosphate into the phenylpyruvic-acids by (NH4)2 SO4-precipitated enzyme preparations were phosphoenolpyruvic-acid, NADH2 and MgCl2 at pH 8[center dot]2. Boiled crude extract and phosphorylated sugar stimulated the conversion and were sometimes obligatory requirements for old preparations.