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Muscle Disorders
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
Kourosh Rezania, Peter Pytel, Betty Soliven
Autosomal recessive disorder due to phosphofructokinase (PFK) deficiency. PFK gene is mapped to chromosome 12. PFK catalyzes the conversion of fructose-6-phosphate to fructose-1, 6-diphosphate in muscle, which is the rate-limiting step in the glycolytic pathway.
The Bioenergetics of Mammalian Sperm Motility
Published in Claude Gagnon, Controls of Sperm Motility, 2020
About 50% of the fructose 1,6-bisphosphate produced by phosphofructokinase is recycled to fructose 6-phosphate and this is nearly independent of glycolytic flux. At low glycolytic flux, substrate cycling consumes all or nearly all the ATP produced by the conversion of glucose to lactate and the pathway probably serves as source of pyruvate for mitochondrial respiration. Futile substrate cycling also occurs in boar and rat spermatozoa. In the boar, increased cycling of hexose phosphates accounts for a large part of the decrease in net glycolytic flux when pyruvate and lactate are added to the incubation.6
Anaerobic endurance: the speed endurance sports
Published in Nick Draper, Helen Marshall, Exercise Physiology, 2014
As the catalyst for the third step in the glycolytic pathway, phosphofructokinase activity is increased with the accumulation of its substrate, fructose-6-phosphate. In addition, a range of metabolites are involved in its control. At rest, skeletal muscle contains higher concentrations of ATP and PCr, while levels of ADP, AMP, Pi and are low. In this situation, PFK activity is inhibited by the high ATP and PCr concentrations. Additionally, H+ enhance the inhibition by ATP, and citrate, found in the cytoplasm when aerobic metabolism is meeting the energy demands (refer to Chapter 12 for further detail), acts as an inhibitor of PFK.
PFKFB3 downregulation aggravates Angiotensin II-induced podocyte detachment
Published in Renal Failure, 2023
Xiaoxiao Huang, Zhaowei Chen, Zilv Luo, Yiqun Hao, Jun Feng, Zijing Zhu, Xueyan Yang, Zongwei Zhang, Jijia Hu, Wei Liang, Guohua Ding
The homodimeric and bifunctional enzyme family of phosphofructokinase-2/Fructose-2,6-bisphosphatase (PFK-2/PFKFB) promotes glycolysis by increasing levels of fructose-2,6-bisphosphate (F2,6P2), which in turn activates the key rate-limiting enzyme 6-phosphofructo-1-kinase (PFK-1) and enhances the conversion of fructose-6-phosphate (F6P) to fructose-1,6-bisphosphate (F1,6P2) in the glycolytic pathway. This causes increased glycolytic flux and increased ATP and NADH production [16]. Among the PFKFB family of four enzymes (PFKFB1-4), PFKFB3 has the highest ratio of kinase to phosphatase activity, which ensures a high glycolytic rate [17]. Recent findings have indicated that PFKFB3 exerts protective effects on the kidneys [18] and promotes the activation of cyclin-dependent kinase-1(cdk1) [19], which promotes talin1 phosphorylation [20]. Excessive talin1 phosphorylation promotes integrin beta1 subunit (ITGB1) activity on the cell surface [21]. Active ITGB1 is an important adhesion molecule on the surface of podocytes, and its activation enhances podocyte adhesion capacity [22–25]. Inhibiting PFKFB3 significantly reduces the expression of cell adhesion molecules, resulting in diminished cell adhesion [26–29]. Therefore, we speculated that Ang II could inhibit talin1 phosphorylation and ITGB1 activation through downregulating PFKFB3 expression. Therefore, we investigated the role of PFKFB3 in Ang II-induced podocyte injury and identified a novel target for CKD treatment.
Glucose metabolism inhibitor PFK-015 combined with immune checkpoint inhibitor is an effective treatment regimen in cancer
Published in OncoImmunology, 2022
Jia Bo Zheng, Chau Wei Wong, Jia Liu, Xiao-Jing Luo, Wei-Yi Zhou, Yan-Xing Chen, Hui-Yan Luo, Zhao-Lei Zeng, Chao Ren, Xiao-Ming Xie, De-Shen Wang
Glycolysis intensity is regulated by the activity of three physiologically reversible enzymes: hexokinase, phosphofructokinase-1 (PFK-1), and pyruvate kinase. PFK-1 is the main rate-limiting enzyme of glycolysis and the activity of PFK-1 is regulated by metabolic products such as adenosine triphosphate (ATP), adenosine diphosphate (ADP), and fructose 2–6 biphosphate.4 Of these compounds, F-2-6-BP is a reaction product catalyzed by 6-phosphofructose 2-kinase/fructose-2,6-biphosphatase (PFK-2/FBPase-2/PFKFB), which is also the most potent positive allosteric effector of PFK-1.4,5 PFKFB is a bifunctional enzyme responsible for the catalyzation of both the synthesis and degradation of F-2,6-BP mediated through its N-terminal domain (2-kase) and C-terminal domain (2-pase) respectively. Of note, the active site of the 2-kase domain has 2 distinct key areas (the F-6-P binding loop and the ATP-binding loop) which are essential for PFKFB to function.6
Screening tools for hereditary hemolytic anemia: new concepts and strategies
Published in Expert Review of Hematology, 2021
Elisa Fermo, Cristina Vercellati, Paola Bianchi
Hereditary hemolytic anemias may also be caused by deficiencies of enzymes of the erythrocyte metabolism, that is composed by three main pathways: glycolysis, the main source of metabolic energy in the erythrocytes, pentose phosphate pathway, and nucleotide metabolism. G6PD deficiency is the most widespread erythroenzymopathy, and is usually associated with acute hemolysis caused by oxidative stress, with the exception of the class-I variants, that result in chronic hemolytic anemia. Pyruvate kinase (PK) deficiency is the most frequent enzymopathy affecting glycolysis, followed by glucose ephosphate isomerase (GPI), whereas pyrimidine 5′-nucleotidase (P5′N) and adenylate kinase (AK) deficiency involve the nucleotide metabolism. Some enzymes, such as triose phosphate isomerase (TPI), phosphoglycerate kinase (PGK) and phosphofructokinase (PFK), are not confined to the red cells but also expressed in other tissues; in such cases, hemolytic anemia may be accompanied to non-hematological symptoms such as myopathy, neuromuscular impairment and mental retardation [5–7].