High impact information on Pfkp

• With glucose, insulin, and palmitate present, stimulation of glucose utilization was rapid and correlated with activation of phosphofructokinase [1].
• The reversal of citrate inhibition by cyclic 3':5'-adenosine monophosphate was also less effective with the thyroid tumor phosphofructokinase, while the protective effect of fructose-6-P was stronger [2].
• Islet phosphofructokinase activity was characterized by inhibition by citrate or high ATP concentrations, and relief from ATP inhibition by AMP [3].
• Cyclic AMP fails to overcome the effect of fasting upon phosphofructokinase [3].
• The thyroid tumor phosphofructokinase showed, however, a greater degree of size and/or shape heterogeneity in the presence of ATP than the normal thyroid enzyme, as determined by gel filtration and sucrose density gradient centrifugation [2].

Biological context of Pfkp

• These results demonstrate that CAV-1 creates binding sites for PFK and ALD that may be of higher affinity than those binding sites localized in the cytoplasm [4].
• It is concluded that the complex allosteric regulation typical of the normal thyroid phosphofructokinase is still present in the enzyme isolated from the thyroid tumor tissue [2].
• Because increased pH stimulates phosphofructokinase activity, the ouabain-insensitive portion of the stimulation of cerebral glucose utilization (CMR(glc)) appears to be due to stimulation of glycolysis by intracellular alkalinization [5].
• Gluconeogenesis in isolated rat hepatic parenchymal cells. IX. Differential effects of glucagon and epinephrine on phosphofructokinase and pyruvate kinase [6].

Anatomical context of Pfkp

• The localization of aldolase (ALD) was also shifted towards the plasma membrane (and colocalized with PFK) in CAV-1 over-expressing cells [4].
• We conclude that CAV-1 functions as a scaffolding protein for PFK, ALD and perhaps other glycolytic enzymes, either through direct interaction or accessory proteins, thus contributing to compartmented metabolism in vascular smooth muscle [4].
• The properties of the near-purified enzyme (specific activity 140 units/mg) were compared with those of phosphofructokinase from normal rat thyroid (specific activity 134 units/mg) [2].
• Phosphofructokinase, glycerol phosphate dehydrogenase and glucose 6-phosphate dehydrogenase were more active in the proximal regions of the epididymis, whereas hexokinase, lactate dehydrogenase and phosphorylase were more active in the distal segment [7].
• When liver cell homogenates were subjected to centrifugation at higher forces (37,400 X g for 60 minutes or greater), the assayable activity of phosphofructokinase in supernatant fractions began to diminish [6].

Associations of Pfkp with chemical compounds

• With glucose alone, stimulation was associated with a rapid decrease in phosphate potential and rapid activation of phosphofructokinase, but an apparently slower activation of glucose transport [1].
• The most notable examples were hexokinase, phosphofructokinase, aldolase, phosphoglycerate kinase, 6-phosphogluconate dehydrogenase and phosphorylase [7].
• Preincubation of tissue supernatant fractions with octanoate or laurate caused an inhibition of the activities of hexokinase and phosphofructokinase [8].
• The observed changes in the glycolytic intermediates may be correlated with the increased activity of phosphofructokinase relative to pyruvate kinase and fructose bisphosphatase [9].
• The low glucose-6-phosphate levels and the enzyme inhibition found, suggested that the phosphorylase b kinase is activated by a mechanism that involves phosphofructokinase [10].

Regulatory relationships of Pfkp

• The activities of phosphofructokinase and pyruvate kinase were not increased by insulin; however, glucagon and mb-cAMP inhibited the assayable activity of phosphofructokinase and pyruvate kinase to 20 to 25% of control values [6].

Other interactions of Pfkp

• The PFK-C and PFK-A isozymes each comprised about half the total and only small amounts of the PFK-B isozyme were present in both regions [11].
• 6. There is a diminished activity of glucokinase and of enzymes of the glycolytic pathway below phosphofructokinase in livers from hypothyroid rats [9].

Analytical, diagnostic and therapeutic context of Pfkp

• Confocal immunofluorescence microscopy was used to study the distribution of phosphofructokinase (PFK) and CAV-1 in the transfected cells [4].

References