Isolation and characterization of phosphofructo 2-kinase from chicken erythrocytes.
1. Phosphofructo 2-kinase from chicken erythrocytes copurifies with fructose 2,6-bisphosphatase activity, suggesting that the enzyme is bifunctional. 2. Similarly to phosphofructo 2-kinase from other tissues it is activated by inorganic phosphate, and inhibited by phosphoenol pyruvate, sn-glycerol 3-phosphate and citrate. However, it has some characteristics different than those of chicken liver phosphofructo 2-kinase, indicating that it is a distinct isozyme. 3. The phosphofructo 2-kinase/fructose 2,6-bisphosphatase activity ratio of the erythrocyte enzyme is one order of magnitude higher than that of the enzyme from liver. In contrast with the chicken liver enzyme, phosphofructo 2-kinase from chicken erythrocytes is activated by dithiothreitol and its activity increases with pH. 4. Chicken erythrocyte phosphofructo 2-kinase activity is neither modified by cyclic AMP-dependent protein kinase or casein kinase I and II. In contrast, it is partially inhibited by protein kinase C.
Espinet
C
C
Unitat de Bioquímica, Facultat de Medicina, Universitat de Barcelona, Spain.
Bartrons
R
R
Carreras
J
J
D000818:Animals; D002645:Chickens; D004912:Erythrocytes / Q000201:enzymology*; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D010732:Phosphofructokinase-1 / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism
D007527:Isoenzymes; D010732:Phosphofructokinase-1; D011493:Protein Kinase C