Figure 1.

Overview of C1 metabolism and its compartmentation in plant cells. 1, SHMT; 2, Gly decarboxylase; 3, 5,10-methylene-THF dehydrogenase; 4, 5,10-methenyl-THF cyclohydrolase; 5, FTHFS; 6, 5,10-methylene-THF reductase; 7, 5-formyl-THF cycloligase; 8, methionyl-tRNA formyltransferase; 9, glycinamide ribonucleotide transformylase and aminoimidazole carboximide ribonucleide transformylase; 10, thymidylate synthase; 11, Met synthase; 12, AdoMet synthetase; 13, AdoMet-dependent methyltransferase; 14, AdoHcy hydrolase; 15, ketopantoate hydroxymethyltransferase; 16, 10-formyl-THF deformylase. Ado, adenosine; THF and its derivatives: CH₃- (methyl), CH₂- (methylene), CH⁺- (methenyl), 5-CHO-, and 10-CHO- (formyl).