Heart mitochondria metabolize 3-methylthiopropionate to CO2 and methanethiol.
3-Methylthiopropionate (MTP) stimulates respiration of substrate-depleted heart mitochondria. This is blocked by uncouplers and by malonate. With the use of methyl-14C- and uniformly 14C-labeled MTP, it was found that methanethiol and CO2 are reaction products. The methyl carbon was not significantly oxidized. This study, together with a recent report [P. W. D. Scislowski et al. (1987) Biochem. J. 247, 35-40], demonstrates the existence of a transsulfuration independent pathway of methionine metabolism by muscle, and that the complete pathway following the initial transamination is a mitochondrial process. The data suggest that MTP is oxidized via acetyl-CoA.
Scislowski
P W
PW
Indiana University School of Medicine, Department of Biochemistry, Indianapolis 46202-5122.
Bremer
J
J
van Thienen
W I
WI
Davis
E J
EJ
D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism*; D008715:Methionine / Q000378:metabolism; D008929:Mitochondria, Heart / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D011422:Propionates / Q000378:metabolism*; D051381:Rats; D013438:Sulfhydryl Compounds / Q000378:metabolism*
D011422:Propionates; D013438:Sulfhydryl Compounds; D002245:Carbon Dioxide; C005231:methylmercaptan; C017526:3-methylthiopropionate; D008715:Methionine; D010100:Oxygen