English: Traditional metabolic architecture comparison of the yeast-specific XuMP pathway and the bacteria-specific RuMP cycle based on the assumption that reactions take partly place in the cytosol. The flux routing of both pathways is highlighted as shaded arrows (purple, XuMP; orange, RuMP). It has to be underlined that both pathways share all reactions of the non-oxidative pentose phosphate pathway. The figure highlights in this context the distinct routes and the interconnection. Therefore, both pathways rely closely on the regeneration of a pentose, xylulose 5-phosphate or ribulose 5-phosphate, respectively, which are condensed with formaldehyde for C₁-assimilation. Key enzymes of methanol oxidation, XuMP and RuMP are shown in white, purple or orange circles, respectively. AOX: alcohol oxidase (1); DAS: dihydroxyacetone synthase (2); DAK: dihydroxyacetone kinase (3); HPS: hexulose-6-phosphate synthase (4); PHI: hexulose-6-phosphate isomerase (5). Metabolite abbreviations are: G6P: glucose 6-phosphate; 6PGL: 6-phosphogluconolactone; RU5P: ribulose 5-phosphate; HU6P: hexulose 6-phosphate; R5P: ribose 5-phosphate; XU5P: xylulose 5-phosphate; S7P: sedoheptulose 7-phosphate; SBP: sedoheptulose 1,7-bisphosphate; E4P: erythrose 4-phosphate; F6P: fructose 6-phosphate; F1,6BP: fructose 1,6-bisphosphate; G3P: glyceraldehyde 3-phosphate; DHA: dihydroxyacetone; DHAP: dihydroxyacetonephosphate; O₂: molecular oxygen; CO₂: molecular carbon dioxide; H₂O₂: molecular hydrogen peroxide; NAD(P)⁺: oxidized nicotinamide adenine dinucleotide (phosphate); NAD(P)H: reduced nicotinamide adenine dinucleotide (phosphate); ADP: adenosine diphosphate; ATP: adenosine triphosphate; Pi: inorganic phosphate