Identification of protein-arginine N-methyltransferase as 10-formyltetrahydrofolate dehydrogenase.
S-Adenosylmethionine:protein-arginine N-methyltransferase (EC 2.1.1. 23; protein methylase I) transfers the methyl group of S-adenosyl-L-methionine to an arginine residue of a protein substrate. The homogeneous liver protein methylase I was subjected to tryptic digestion followed by reverse phase high performance liquid chromatography (HPLC) separation and either "on-line" mass spectrometric fragmentation or "off-line" Edman sequencing of selected fractions. Data base searching of both the mass spectrometric and Edman sequencing data from several peptides identified the protein methylase as 10-formyltetrahydrofolate dehydrogenase (EC 1.5.1.6; Cook, R. J., Lloyd, R. S., and Wagner, C. (1991) J. Biol. Chem. 266, 4965-4973; Swiss accession number). This identification was confirmed by comparative HPLC tryptic peptide mapping and affinity chromatography of the methylase on the 5-formyltetrahydrofolate-Sepharose affinity gel used to purify the dehydrogenase. The purified rat liver methylase had approximately 33% of the 10-formyltetrahydrofolate dehydrogenase and 36% of the aldehyde dehydrogenase activity as compared with the recombinant dehydrogenase, which also had protein methylase I activity. Polyclonal antibodies against recombinant dehydrogenase reacted with protein methylase I purified either by polyacrylamide gel electrophoresis or 5-formyltetrahydrofolate affinity chromatography. In each instance there was only a single immunoreactive band at a molecular weight of approximately 106,000. Together, these results confirm the co-identity of protein-arginine methyltransferase and 10-formyltetrahydrofolate dehydrogenase.
Kim
S
S
Department of Biochemistry, Korea University Medical College, Graduate School of Biotechnology, Korea University, Seoul, 136-701, Korea. sdkim@kuccnx.korea.ac.kr
Park
G H
GH
Joo
W A
WA
Paik
W K
WK
Cook
R J
RJ
Williams
K R
KR
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D002955:Leucovorin / Q000737:chemistry; D008099:Liver / Q000201:enzymology; D008969:Molecular Sequence Data; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000737:chemistry* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D010449:Peptide Mapping; D011484:Protein-Arginine N-Methyltransferases / Q000737:chemistry* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D012685:Sepharose / Q000737:chemistry; D017421:Sequence Analysis; D000099295:Formyltetrahydrofolate Dehydrogenase
D002955:Leucovorin; D000587:Oxidoreductases Acting on CH-NH Group Donors; D011484:Protein-Arginine N-Methyltransferases; D011994:Recombinant Proteins; D012685:Sepharose; D000099295:Formyltetrahydrofolate Dehydrogenase