Mammalian glycine N-methyltransferases. Comparative kinetic and structural properties of the enzymes from human, rat, rabbit and pig livers.
1. Human liver contains a rather high level of glycine N-methyltransferase. 2. The enzymes from human, rat, rabbit and pig livers are all tetramers and exhibit positive cooperativity toward S-adenosylmethionine and Michaelis-Menten kinetics toward glycine. The [S]0.5 values for S-adenosylmethionine and glycine of the rat enzyme are considerably lower than those of three other enzymes. 3. The subunit of rat glycine N-methyltransferase is shorter by two residues compared with the subunits of human, rabbit and pig glycine N-methyltransferases. Except for this difference, however, all enzymes show a high degree of sequence homology.
Ogawa
H
H
Department of Biochemistry, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Japan.
Gomi
T
T
Fujioka
M
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005260:Female; D050938:Glycine N-Methyltransferase; D006801:Humans; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D008780:Methyltransferases / Q000737:chemistry / Q000378:metabolism*; D008875:Middle Aged; D008969:Molecular Sequence Data; D011817:Rabbits / Q000378:metabolism*; D051381:Rats / Q000378:metabolism*; D012689:Sequence Homology, Nucleic Acid; D013552:Swine / Q000378:metabolism*
D008780:Methyltransferases; C494510:GNMT protein, human; D050938:Glycine N-Methyltransferase