Inhibition by fructose 1,6-bisphosphate of transaldolase from Escherichia coli

Ogawa, Tadashi
Murakami, Keiko
Yoshino, Masataka

Department of Biochemistry, School of Medicine, Aichi Medical University, Yazako-Karimata 1-1, Nagakute, Aichi 480-1195, Japan

Corresponding author: Department of Biochemistry, School of Medicine, Aichi Medical University, Yazako-Karimata 1-1, Nagakute, Aichi 480-1195, Japan. Tel: +81 561 61 4056; E-mail: [email protected]

Present address: Department of Legal Medicine, School of Medicine, Aichi Medical University, Yazako-Karimata 1-1, Nagakute, Aichi 480-1195, Japan.

Accepted July 26, 2016

Received in revised form March 27, 2016

FEMS Microbiology Letters (FEMSLE) 363(17), September 2016. | DOI: 10.1093/femsle/fnw183

The effect of fructose 1,6-bisphosphate (Fru 1,6-P₂) on the regulatory enzymes of pentose phosphate pathway of Escherichia coli was examined. Fru 1,6-P₂ inhibited E. coli transaldolase (EC 2.2.1.2) competitively against fructose 6-phosphate and uncompetitively against erythrose 4-phosphate, whereas Fru 1,6-P₂ did not affect glucose 6-phosphate dehydrogenase (EC 1.1.1.49) and 6-phosphogluconate dehydrogenase (EC 1.1.1.44). Kinetic results can be explained by assuming that transaldolase has two kinds of binding sites for Fru 1,6-P₂: a competitive binding site for fructose 6-phosphate and a second binding site on the enzyme-erythrose 4-phosphate complex. Fru 1,6-P₂ increased resulting from the stimulation of glycolysis, can inhibit transaldolase and further participates in the elevation of the concentration of ribose 5-phosphate that can be preferentially utilized for anabolic reaction in exponential phase of E. coli.