5-Methylthioribose kinase. A new enzyme involved in the formation of methionine from 5-methylthioribose

J Biol Chem. 1978 Sep 10;253(17):6021-5.


The presence of a previously unidentified enzyme, tentatively designated 5-methylthioribose kinase, has been demonstrated in cell-free extracts of Enterobacter aerogenes. The enzyme catalyzes the ATP-dependent phosphorylation of 5-methylthioribose. ADP is one of the products of the reaction and, based on functional group analyses, the other product is 5-methylthioribose 1-phosphate. A 40-fold purified enzyme preparation has been obtained from a cell-free extract of E. aerogenes. Activity of the partially purified enzyme is totally dependent on the presence of a divalent cation and a sulfhydryl reagent. The substrate specificity of the enzyme is quite narrow, and the Km values for ATP and 5-methylthioribose are 7.4 X 10(-5) M and 8.1 X 10(-6) M, respectively. These results suggest that 5-methylthioribose kinase may be a primary enzyme involved in the recycling of the methylthio group of 5-methylthioribose back into methionine.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cations, Divalent
  • Enterobacter / enzymology*
  • Enterobacteriaceae / enzymology*
  • Kinetics
  • Methionine
  • Phosphotransferases (Alcohol Group Acceptor)
  • Phosphotransferases / isolation & purification
  • Phosphotransferases / metabolism*
  • Thioglycosides / metabolism*


  • Cations, Divalent
  • Thioglycosides
  • 5-methylthioribose
  • Methionine
  • Phosphotransferases
  • Phosphotransferases (Alcohol Group Acceptor)
  • 5-methylthioribose kinase