Purification and characterization of ribulose-5-phosphate kinase from spinach

Arch Biochem Biophys. 1986 Feb 15;245(1):14-23. doi: 10.1016/0003-9861(86)90185-2.


An efficient purification procedure utilizing affinity chromatography is described for spinach ribulose-5-phosphate kinase, a light-regulated chloroplastic enzyme. Gel filtration and polyacrylamide gel electrophoresis of the purified enzyme reveal a dimeric structure of 44,000 Mr subunits. Chemical crosslinking with dimethyl suberimidate confirms the presence of two subunits per molecule of native kinase, which are shown to be identical by partial NH2-terminal sequencing. Based on sulfhydryl titrations and on amino acid analyses, each subunit contains four to five cysteinyl residues. The observed slow loss of activity during spontaneous oxidation in air-saturated buffer correlates with the intramolecular oxidation of two sulfhydryl groups, presumably those involved in thioredoxin-mediated regulation.

Publication types

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

MeSH terms

  • Amino Acids / analysis
  • Chromatography, Gel
  • Electrophoresis, Polyacrylamide Gel
  • Molecular Weight
  • Oxidation-Reduction
  • Phosphotransferases (Alcohol Group Acceptor)*
  • Phosphotransferases / isolation & purification*
  • Phosphotransferases / radiation effects
  • Plants / enzymology*
  • Sulfhydryl Compounds / analysis


  • Amino Acids
  • Sulfhydryl Compounds
  • Phosphotransferases
  • Phosphotransferases (Alcohol Group Acceptor)
  • phosphoribulokinase