Figure 1.

Schematic representation of the possible contribution of the glycolate and Phosphorylated Pathways of Ser Biosynthesis (PPSB) to the sulfur metabolism. Enzymes and transporters are highlighted in gray and blue, respectively. Glycolate pathway: GDC, Gly decarboxylase; SHMT, Ser hydroxymethyl transferase. Sulfate assimilation: APK, APS kinase; ATPS, ATP sulfurylase; SIR, sulfite reductase; SULTR, sulfate transporter. Metabolites: 2-PG, 2-phosphoglycolate; 3-PHP, 3-phosphohydroxypyruvate; 3-PS, 3-phospho-Ser; 5,10-CH₂-THF, 5.10-methylene-tetrahydrofolate; APS, adenosine 5′-phosphosulfate; Cys, Cysteine; PAPS, 3′-phosphoadenosine 5′-phosphosulfate; THF, tetrahydrofolate.