Purification of porcine brain protein phosphatase 2A leucine carboxyl methyltransferase and cloning of the human homologue

Biochemistry. 1999 Dec 14;38(50):16539-47. doi: 10.1021/bi991646a.


The carboxyl methyltransferase, which is claimed to exclusively methylate the carboxyl group of the C-terminal leucine residue of the catalytic subunit of protein phosphatase 2A (Leu(309)), was purified from porcine brain. On the basis of tryptic peptides, the cDNA encoding the human homologue was cloned. The cDNA of this gene encodes for a protein of 334 amino acids with a calculated M(r) of 38 305 and a predicted pI of 5.72. Database screening reveals the presence of this protein in diverse phyla. Sequence analysis shows that the novel methyltransferase is distinct from other known protein methyltransferases, sharing only sequence motifs supposedly involved in the binding of adenosylmethionine. The recombinant protein expressed in bacteria is soluble and the biophysical, catalytic, and immunological properties are indistinguishable from the native enzyme. The methylation of PP2A by the recombinant protein is restricted to Leu(309) of PP2A(C). No direct effects on phosphatase activity changes were observed upon methylation of the dimeric or trimeric forms of PP2A.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Brain / enzymology*
  • Cloning, Molecular
  • Enzyme Activation
  • Escherichia coli / enzymology
  • Escherichia coli / genetics
  • Humans
  • Leucine / metabolism
  • Methylation
  • Molecular Sequence Data
  • Phosphoprotein Phosphatases / metabolism*
  • Protein O-Methyltransferase / genetics
  • Protein O-Methyltransferase / immunology
  • Protein O-Methyltransferase / isolation & purification*
  • Protein O-Methyltransferase / metabolism
  • Protein Phosphatase 2
  • Rabbits
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Substrate Specificity
  • Swine


  • Recombinant Proteins
  • C-terminal leucine protein methyltransferase
  • Protein O-Methyltransferase
  • Phosphoprotein Phosphatases
  • Protein Phosphatase 2
  • Leucine

Associated data

  • GENBANK/AF037601