Inhibition of Purine Nucleoside Phosphorylase (PNP) in Micrococcus luteus by Phenylglyoxal

  • Published : 1996.09.01

Abstract

Micrococcus luteus purine nucleoside phosphorylase (PNP) has been purified and characterized. The physical and kinetic properties have been described previously. Chemical modification of the enzyme was attempted to gain insight on the active site. The enzyme was inactivated in a time-dependent manner by the arginine- specific modifying reagent phenylglyoxal. There was a linear relationship between the observed rate of inactivation and the phenylglyoxal concentration. At 30 $^{\circ}C$ the bimolecular rate constant for the modification was 0.015 $min^{-1}mM^{-1}$ in 50 mM $NaHCO_3$ buffer, pH 7.5. The plot of logk versus log phenylglyoxal concentration was a strainght line with a slope value of 0.9, indicating that modification of one arginine residue was needed to inactivate the enzyme. Preincubation with saturated solutions of substrates protected the enzyme from inhibition of phenylglyoxal, indicating that reactions with phenylglyoxal were directed at arginyl residues essential for the catalytic functioning of the enzyme.

Keywords

References

  1. Arch. Biochem. Biophys v.198 Kinetics of inactivation of Escherichia coli glutamate apodecarboxylase by phenyl glyoxal Cheung, S.;Fonda, M.L.
  2. Kor. J. Microbiol. v.31 Kinetic analysis of purine nucleoside phosphorylase in Saccharomyces cerevisiae Choi, H.S.
  3. Kor. J. Microbiol. v.34 Purification and Characterization of PNP in Micrococcus luteus Choi, H.S.
  4. Biochemistry v.13 Essential arginyl residues in Escherichia coli alkaline phosphatase Daemen, F.J.M.;riordan, J.F.
  5. J. Biol. Chem. v.269 Reaction of phenylglyoxal with arginine groups in D-amino acid oxidase from Rhodotrorula gracilis Gadda, G.;Negri, A.;Pilone, M.S.
  6. Eur. J. Biochem. v.51 Purine nucleoside phosphorylase from Eschrichia coli and Salmonella typhymurium Jensen, K.F.;Nygaard, P.
  7. J. Biol. Chem. v.251 Functionally important arginine residues of aspartate transcarbamylase Kantrowitz, E.R.;Lipscomb, W.N.
  8. J. Biol. Chem. v.238 Inactivation of myosin by 2,4-dinitrophenol and protection by adenosine triphosphate and other phosphate compounds Levy, H.M.;Leber P.D.;Ryan, E.M.
  9. Appl. Environment. Microbiol. v.56 Purification and characterization of a novel nucleoside phosphorylase from a Krebsiella sp. and its use in the enzymatic production of adenosine arabinoside Ling, F.;Inou, Y.;Kimura, A.
  10. Developments in Cancer Chemotherapy Purine nucleoside phosphorylase Stoeckler, J.D.
  11. J. Biol. Chem. v.255 An essential arginine residue in porcine phospholipase A2 Vensel, L. A.;Kantrowitz, E.R.
  12. Biochemistry v.33 Arginine 304 is an active site residue in phosphomannose isomerase from Candida albicans Wells, T.N.C.;Scully, P.;Magnenat, E.