Phosphorylation of 6-phosphofructokinase in rat lung.
1. 6-Phosphofructokinase of both fetal and adult rat lung consists of L, M and C subunits in a ratio of 65:25:10. 2. 6-Phosphofructokinase was purified to homogeneity from adult rat lung and subjected to phosphorylation in vitro by the catalytic subunit of cyclic AMP-dependent protein kinase. 3. This resulted in phosphorylation of the L and M subunit of 6-phosphofructokinase. 4. The C subunit was not phosphorylated. 5. However, if the phosphorylation of 6-phosphofructokinase was studied in the cytosol fraction of either fetal or adult lung using endogenous protein kinase(s), only the L subunit was phosphorylated. 6. This phosphorylation was dependent on cyclic AMP. 7. No influence of calcium, calmodulin or phosphatidylserine/diolein on the phosphorylation was observed. 8. It is concluded that although both L and M subunits of rat lung 6-phosphofructokinase are potential substrates for cyclic AMP-dependent protein kinase, their phosphorylation in situ is differentially regulated.
Heesbeen
E C
EC
Department of Haematology, University Hospital, Utrecht, The Netherlands.
Rijksen
G
G
van Golde
L M
LM
Staal
G E
GE
D000375:Aging / Q000378:metabolism; D000818:Animals; D001345:Autoradiography; D003600:Cytosol / Q000201:enzymology; D004591:Electrophoresis, Polyacrylamide Gel; D006878:Hydroxides; D008168:Lung / Q000196:embryology / Q000201:enzymology*; D010732:Phosphofructokinase-1 / Q000378:metabolism*; D010766:Phosphorylation; D011188:Potassium; D017680:Potassium Compounds; D011494:Protein Kinases / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D006878:Hydroxides; D017680:Potassium Compounds; D011494:Protein Kinases; D010732:Phosphofructokinase-1; D011188:Potassium; C029943:potassium hydroxide