Individual enzymes within the FOCM network compete for limited folate cofactors. Cell cycle regulated‐expression, activity and cellular localization of enzymes and pathways in FOCM network enable cells to prioritize individual pathways within the network according to temporal needs. De novo purine and dTMP biosynthesis are regulated by cell cycle through both an increase in enzyme activity and formation of multienzyme complexes. Enzymes in dTMP biosynthesis pathway translocate in the nucleus and form complexes at sites of DNA replication.