Discovery of a Kojibiose Phosphorylase in Escherichia coli K-12. Academic Article uri icon

abstract

  • The substrate profiles for three uncharacterized enzymes (YcjM, YcjT, and YcjU) that are expressed from a cluster of 12 genes ( ycjM-W and ompG) of unknown function in Escherichia coli K-12 were determined. Through a comprehensive bioinformatic and steady-state kinetic analysis, the catalytic function of YcjT was determined to be kojibiose phosphorylase. In the presence of saturating phosphate and kojibiose (-(1,2)-d-glucose-d-glucose), this enzyme catalyzes the formation of d-glucose and -d-glucose-1-phosphate ( kcat = 1.1 s-1, Km = 1.05 mM, and kcat/ Km = 1.12 103 M-1 s-1). Additionally, it was also shown that in the presence of -d-glucose-1-phosphate, YcjT can catalyze the formation of other disaccharides using 1,5-anhydro-d-glucitol, l-sorbose, d-sorbitol, or l-iditol as a substitute for d-glucose. Kojibiose is a component of cell wall lipoteichoic acids in Gram-positive bacteria and is of interest as a potential low-calorie sweetener and prebiotic. YcjU was determined to be a -phosphoglucomutase that catalyzes the isomerization of -d-glucose-1-phosphate ( kcat = 21 s-1, Km = 18 M, and kcat/ Km = 1.1 106 M-1 s-1) to d-glucose-6-phosphate. YcjU was also shown to exhibit catalytic activity with -d-allose-1-phosphate, -d-mannose-1-phosphate, and -d-galactose-1-phosphate. YcjM catalyzes the phosphorolysis of -(1,2)-d-glucose-d-glycerate with a kcat = 2.1 s-1, Km = 69 M, and kcat/ Km = 3.1 104 M-1 s-1.

published proceedings

  • Biochemistry

author list (cited authors)

  • Mukherjee, K., Narindoshvili, T., & Raushel, F. M.

citation count

  • 15

complete list of authors

  • Mukherjee, Keya||Narindoshvili, Tamari||Raushel, Frank M

publication date

  • April 2018