Phosphofructokinase in rat lung during perinatal development: characterization of subunit composition and regulation by fructose 2,6-bisphosphate and glucose 1,6-bisphosphate.
The subunit composition of phosphofructokinase (ATP: D-fructose-6-phosphate-1-phosphotransferase, EC 2.7.1.11) was studied in rat lung during perinatal development. No change in subunit composition during this period was observed. The three subunits of phosphofructokinase (L, M and C) were present in a ratio of approx. 65:25:10, respectively. In addition the levels of two effectors of phosphofructokinase were determined in rat lung during perinatal development: glucose 1,6-bisphosphate and fructose 2,6-bisphosphate. Until day 20 of gestation (term is 22 days) the glucose 1,6-bisphosphate level remains relatively constant (approx. 0.55 mumol/g protein), decreases before birth and increases sharply up to 1.04 mumol/g protein 2 days after birth. The amount of fructose 2,6-bisphosphate in rat lung shows a different developmental profile. A small peak is shown at day 17 of gestation whereas a larger peak up to 36.4 nmol/g protein is shown at days 20 and 21 of gestation. The time of maximal fructose 2,6-bisphosphate content corresponds with the time of glycogen breakdown and acceleration of surfactant synthesis in prenatal rat lung. Both glucose 1,6-bisphosphate and fructose 2,6-bisphosphate stimulate lung phosphofructokinase. Half maximal stimulations occur in the range of 24.1-70.9 microM glucose 1,6-bisphosphate and 0.17-0.34 microM fructose 2,6-bisphosphate.
D000367:Age Factors; D000818:Animals; D004789:Enzyme Activation; D005635:Fructosediphosphates / Q000502:physiology*; D005865:Gestational Age; D019298:Glucose-6-Phosphate / Q000031:analogs & derivatives*; D005958:Glucosephosphates / Q000502:physiology*; D006598:Hexosediphosphates / Q000502:physiology*; D008168:Lung / Q000196:embryology / Q000201:enzymology* / Q000254:growth & development; D046911:Macromolecular Substances; D010732:Phosphofructokinase-1 / Q000378:metabolism*; D051381:Rats
D005635:Fructosediphosphates; D005958:Glucosephosphates; D006598:Hexosediphosphates; D046911:Macromolecular Substances; D019298:Glucose-6-Phosphate; C027652:fructose 2,6-diphosphate; C016473:glucose-1,6-bisphosphate; D010732:Phosphofructokinase-1