In response to radiation in B16 cells, the contents of glutamate, alanine, glycine, and choline were increased, which indicated that the activity of aspartate transaminase (AST), alanine transaminase (ALT), and alanine-glyoxylate transaminase (AGT) was elevated. Therefore, we speculate that, with a series of biochemical reactions upon the catalysis of those enzymes, more glycine may be synthesized to participate in DNA damage repair. On the other hand, with the catalysis of phosphatidylcholine (PC) synthase, serine can react with PC to generate choline and phosphatidylserine (PS). Though we did not observe PC and PS in cellular soluble metabolites upon radiation, due to their poor water solubility (no corresponding signal was observed in the hydrogen spectrum), the elevated content of choline in response to radiation indicated that the catalytic reaction occurred.