Cloning, sequencing, and heterologous expression of rat methionine synthase cDNA

Kazuhiro Yamada, Takamasa Tobimatsu, Tetsuo Toraya

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Methionine synthase catalyzes cobalamin-dependent methyl transfer reaction from 5-methyltetrahydrofolate to homocysteine, forming methionine. Rat methionine synthase cDNA was cloned and analyzed by RT-PCR, 3′- and 5′-RACE techniques. The cDNA consists of a 0.3-kb upstream untranslated region, a 3.8-kb coding region, and a 0.4-kb downstream untranslated region. The open reading frame encoded a polypeptide of 1,253 amino acid residues with a calculated molecular weight of 139,162. This molecular weight was in good agreement with the observed one (143,000) of the purified rat liver enzyme. The deduced amino acid sequence was 53, 92, and 64% identical with those of the Escherichia coli, human, and presumptive Caenorhabditis elegans enzymes, respectively. All the fingerprint sequences, forming parts of the cobalamin- and S-adenosylmethionine-binding sites, were completely conserved in the rat methionine synthase. A high-level expression of catalytically active enzyme in insect cells was done by infection with a baculovirus containing the rat methionine synthase cDNA.

Original languageEnglish
Pages (from-to)2155-2160
Number of pages6
JournalBioscience, Biotechnology and Biochemistry
Issue number11
Publication statusPublished - 1998


  • Cdna cloning
  • Cobalamin
  • Methionine synthase
  • Rat
  • Vitamin B

ASJC Scopus subject areas

  • Biotechnology
  • Analytical Chemistry
  • Biochemistry
  • Applied Microbiology and Biotechnology
  • Molecular Biology
  • Organic Chemistry


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