Substrate Specificity of Thymidine Phosphorylase of E. Coli: Role of Hydroxyl Groups

Abstract

Substrate specificity of E. coli thymidine phosphorylase to pyrimidine nucleoside modified at 5 ′-, 3 ′-, and 2 ′-positions of sugar moiety has been studied. Equilibrium (K_eq) and kinetics constants of phosphorolysis reaction of nucleosides were measured. The most important hydrogen bonds in enzyme-substrate complex have been determined.

Keywords:

• Thymidine phosphorlase
• substrate specificity
• thymidine derivatives

This manuscript was presented at the 2006 Round Table Conference, XVII International Roundtable, Bern, Switzerland, September 3–7, 2006.

Financial support of the Russian Foundation for Basic Research is acknowledged.

Notes

^a The kinetic parameters for phosphorolysis of thymidine analogs in the presence of TP were determined spectrophotometrically.^{[ 8 ]} The equilibrium constants were measure using HPLC at pH 6.5 and 37°C.^{[ 8 ]}