Purification and characterization of homodimeric methylmalonyl-CoA mutase from Sinorhizobium meliloti

Arch Microbiol. 2003 Aug;180(2):151-4. doi: 10.1007/s00203-003-0570-3. Epub 2003 Jul 3.


High activity (>60 munit/mg protein) of 5'-deoxyadenosylcobalamin-dependent methylmalonyl-CoA mutase (EC was constantly found during growth of a strain of the root-nodule-forming bacterium Sinorhizobium meliloti harboring an extra plasmid-encoded copy of the methylmalonyl-CoA-mutase-encoding bhbA gene. The enzyme was purified to homogeneity and characterized. The purified enzyme was found to be a colorless apo-form. The apparent molecular weight of the enzyme was calculated to be 165,000+/-5,000 by Superdex 200 HR gel filtration. SDS-PAGE of the purified enzyme resolved one protein band with an apparent molecular mass of 80.0+/-2.0 kDa, indicating that the S. meliloti enzyme is composed of two identical subunits. The NH(2)-terminal sequence was identical to that predicted from the bhbA nucleotide sequence. Monovalent cations were required for enzyme activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoenzymes / isolation & purification
  • Chromatography, Gel
  • Cobamides
  • Dimerization
  • Electrophoresis, Polyacrylamide Gel
  • Enzyme Activation
  • Holoenzymes / metabolism
  • Kinetics
  • Methylmalonyl-CoA Mutase / biosynthesis
  • Methylmalonyl-CoA Mutase / chemistry*
  • Methylmalonyl-CoA Mutase / isolation & purification*
  • Methylmalonyl-CoA Mutase / metabolism
  • Molecular Weight
  • Protein Subunits
  • Sinorhizobium meliloti / enzymology*
  • Sinorhizobium meliloti / growth & development


  • Apoenzymes
  • Cobamides
  • Holoenzymes
  • Protein Subunits
  • Methylmalonyl-CoA Mutase
  • cobamamide