Involvement of methionine in the synthesis of certain membrane-associated nucleotide sugars by human amnion (WISH) cells

A plasma membrane preparation from human amnion (WISH) cells contained uridine diphosphate sugars and methyluridine diphosphate (mUDP) sugars. The synthesis of mUDP-glucose, mUDP-mannose, and mUDP-fucose by the membrane preparation occurred when supplemented with uridine-5′-diphosphate-glucose and S-adenosyl-l-methionine. It is suggested that this newly recognized route for fucose biosynthesis might be employed by certain transformed cells, and may partly account for the methionine dependence of certain human tumors. Additionally, it is suggested that, in colon cancer, a deficiency of folic acid and methionine might affect mUDP-sugar biosynthesis rather than the methylation of DNA.