Figure 7.

Proposed metabolic pathway involved in methanol assimilation by sycamore cells (the origin of methyl-β-d-glucopyranoside is not indicated). Enzymes: 1, Formyltetrahydrofolate synthetase; 2, methenyl H₄Pte-Glu_n cyclohydrolase; 3, methylenetetrahydrofolate dehydrogenase; 4, Ser hydroxymethyltransferase; 5, Gly decarboxylase; 6, methylenetetrahydrofolate reductase; 7, cobalamin-independent Met synthase; 8, S-adenosyl-Met synthetase; 9, methyltransferase; 10, S-adenosylhomo-Cys hydrolase; 11, cystathionine γ-synthase and cystathionine β-lyase; 12, methanol oxidase and formaldehyde dehydrogenase. H₄FGlu_n, 5,6,7,8 tetrahydropteroylpoly-Glu (tetrahydrofolate); CHOH₄F-Glu_n, 10-formyltetrahydrofolate; CHH₄F-Glu_n, 5,10-methenyltetrahydrofolate; CH₂H₄F-Glu_n, 5,10-methylenetetrahydrofolate; CH₃H₄FGlu_n, 5-methyltetrahydrofolate; SAM, S-adenosyl-Met; SAH, S-adenosylhomo-Cys. ●, (¹³C) carbon.