Figure 4.

Simplified scheme of carbohydrate metabolism in K. lactis. The enzymes discussed in this work are highlighted in large red letters; other important enzymes are designated in smaller red letters. Cofactors are shown in blue. Glycolytic reactions are shown in the center of the upper part and to the right in the lower part. Directions of glycolysis and gluconeogenesis are indicated by bold arrows at the right. PPP designates the pentose phosphate pathway, GC the glyoxylate cycle (note that compartmentalization of the latter reactions is not depicted, here). Mitochondria are represented by the elliptical light-blue structure at the lower left. Dashed arrows indicate the action of multiple enzymes not specified for clarity. For more detailed schemes of the connected pathways, two former works may be consulted [18,47]. Enzyme abbreviations are: KlHxk1 = hexokinase, KlPgi1 = phosphoglucose isomerase, KlPfk1/2 = the hetero-octameric phospho-fructokinase formed by two types of subunits, KlTkl1 = transketolase, KlTal1 = transaldolase, KlFba1 = fructose-1,6-bisphosphate aldolase, KlTpi1 = triosephosphate isomerase, KlTdh1, KlTdh2 = NAD⁺-dependent glyceraldehyde-3-phosphate dehydrogenases, KlGdp1 = NAD⁺/NADP⁺-dependent glyceraldehyde-3-phosphate dehydrogenase, KlGut1 = glycerol kinase, KlGut2 = glycerol-3-phosphate dehydrogenase. Metabolite abbreviations: G-6-P = glucose-6-phosphate, F-6-P = fructose-6-phosphate, F-1,6-P₂ = fructose-1,6-bisphosphate, DHAP = dihydroxyacetone phosphate, GAP = glyceraldehyde-3-phosphate, G3P = glycerol-3-phosphate, S-7-P = sedoheptulose-7-phosphate, E-4-P = erythrose-4-phosphate, 1,3-PGA = 1,3-bisphosphoglycerate, PEP = phosphoenolpyruvate, Ac-CoA = acetyl-coenzyme A.