Interaction of storage carbohydrates and other cyclic fluxes with central metabolism: A quantitative approach by non-stationary 13C metabolic flux analysis.
Metab Eng Commun
; 3: 52-63, 2016 Dec.
Article
in En
| MEDLINE
| ID: mdl-29468113
ABSTRACT
13C labeling experiments in aerobic glucose limited cultures of Saccharomyces cerevisiae at four different growth rates (0.054; 0.101, 0.207, 0.307 h-1) are used for calculating fluxes that include intracellular cycles (e.g., storage carbohydrate cycles, exchange fluxes with amino acids), which are rearranged depending on the growth rate. At low growth rates the impact of the storage carbohydrate recycle is relatively more significant than at high growth rates due to a higher concentration of these materials in the cell (up to 560-fold) and higher fluxes relative to the glucose uptake rate (up to 16%). Experimental observations suggest that glucose can be exported to the extracellular space, and that its source is related to storage carbohydrates, most likely via the export and subsequent extracellular breakdown of trehalose. This hypothesis is strongly supported by 13C-labeling experimental data, measured extracellular trehalose, and the corresponding flux estimations.
2PG, 2-phosphoglycerate; 3PG, 3-phosphoglycerate; 6PG, 6-phospho gluconate; ACO, aconitate hydratase; AK, adenylate kinase; ALA, alanine; ASP, aspartate; Amino acids; CoA, coenzyme-A; DHAP, dihydroxy acetone phosphate; DO, dissolved oxygen; E4P, erythrose-4-phosphate; ENO, phosphopyruvate hydratase; F6P, fructose-6-phosphate; FBA, fructose-bisphosphate aldolase; FBP, fructose-1,6-bis-phosphate; FMH, fumarate hydratase; FUM, fumarate; Flux estimation; G1P, glucose-1-phosphate; G6P, glucose-6-phosphate; G6PDH, glucose-6-phosphate dehydrogenase; GAP, glyceraldehyde-3-phosphate; GAPDH&PGK, glyceraldehyde-3-phosphate dehydrogenase+phosphoglycerate kinase; GLN, glutamine; GLU, glutamate; GLY, glycine; GPM, phosphoglycerate mutase; Glycogen; IDMS, Isotope dilution mass spectrometry; Iso-Cit, isocitrate; LEU, leucine; LYS, lysine; MAL, malate; METH, methionine; Non-stationary 13C labeling; OAA, oxaloacetate; OUR, Oxygen uptake rate; PEP, phospho-enol-pyruvate; PFK, 6-phosphofructokinase; PGI, glucose-6-phosphate isomerase; PGM, phosphoglucomutase; PMI, mannose-6-phosphate isomerase; PPP, pentose phosphate pathway; PRO, proline; PYK, pyruvate kinase; PYR, pyruvate; RPE, ribulose-phosphate 3-epimerase; RPI, ribose-5-phosphate isomerase; Rib5P, ribose-5-phosphate; Ribu5P, ribulose-5-phosphate; S7P, sedoheptulose-7-phosphate; SER, serine; SUC, succinate; T6P, trehalose-6-phosphate; TCA, tricarboxylic acid cycle.; TPP, trehalose- phosphatase; TPS, alpha,alpha-trehalose-phosphate synthase; Trehalose; UDP, uridine-5-diphosphate; UDPG, UDP-glucose; UTP, uridine-5-triphosphate; X5P, xylulose-5-phosphate; α-KG, oxoglutarate
Full text:
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Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Metab Eng Commun
Year:
2016
Document type:
Article
Affiliation country:
Países Bajos