Cassady sandbox1: Difference between revisions
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{{STRUCTURE_1pfk | PDB=1pfk | SCENE= }} | {{STRUCTURE_1pfk | PDB=1pfk | SCENE= }} | ||
Phosphofructokinase (PFK) (PDB id [[4pfk]]) is an approximately 300 residue enzyme that catalyzes the phosphorylation of Fructose-6-phosphate (F6P) to Fructose-1,6-bisphosphate (F1,6P) | Phosphofructokinase (PFK) (PDB id [[4pfk]]) is an approximately 300 residue enzyme that catalyzes the phosphorylation of Fructose-6-phosphate (F6P) to Fructose-1,6-bisphosphate (F1,6P). | ||
==Role in Glycolysis== | ==Role in Glycolysis== | ||
Glycolysis is the process for preparing, and breaking down, glucose to make pyruvic acid, which is used in anaerobic respiration or as one of the starting reactants in the citric acid cycle. Three points in the process of glycolysis occur with a large negative free energy and are therefore, irreversible. These three points are hexokinase, phosphofructokinase, and pyruvate kinase; of these three PFK is considered the major regulatory point for glycolysis in muscle with a ΔG= -25.9 kJ/mol. <ref>Voet, Donald, Judith G. Voet, and Charlotte W. Pratt. Fundamentals of Biochemistry: Life at the Molecular Level. Hoboken, NJ: Wiley, 2008. Print.</ref> | Glycolysis is the process for preparing, and breaking down, glucose to make pyruvic acid, which is used in anaerobic respiration or as one of the starting reactants in the citric acid cycle. Three points in the process of glycolysis occur with a large negative free energy and are therefore, irreversible. These three points are hexokinase, phosphofructokinase, and pyruvate kinase; of these three PFK is considered the major regulatory point for glycolysis in muscle with a ΔG= -25.9 kJ/mol. <ref>Voet, Donald, Judith G. Voet, and Charlotte W. Pratt. Fundamentals of Biochemistry: Life at the Molecular Level. Hoboken, NJ: Wiley, 2008. Print.</ref> | ||
==Structure== | |||
It is a <scene name='Zach_Westrick_Sandbox/Tetramer/1'>Homotetramer</scene> that acts as a dimer of dimers, similar to hemoglobin.<ref>PMID:6115424</ref> One half of each dimer is involved in the binding of ATP, while the other is involved with substrate binding and also contains an allosteric site. <ref>PMID:2975709</ref> The <scene name='Zach_Westrick_Sandbox/Secondary_structure/3'>Secondary Structure</scene> puts it in an alpha and beta class. Each unit is comprised of two domains that sandwich parallel beta sheets in between alpha helices. The outer most beta sheets of the larger domain, however, are anti-parallel. This is best seen in the <scene name='Zach_Westrick_Sandbox/One_subunit/1'>4pfk image</scene> Phosphofructokinase is not only the enzymes name, but also, the fold, superfamily, and family classification name. | |||
==Mechanism and Regulation of Phosphofructokinase== | ==Mechanism and Regulation of Phosphofructokinase== | ||
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The PFK's Km for ATP is .020mM and .032mM.<ref>PMID: 6233271</ref> | The PFK's Km for ATP is .020mM and .032mM.<ref>PMID: 6233271</ref> | ||
[[Image:PFK mech.JPG]] | [[Image:PFK mech.JPG]] | ||
==Additional Resources== | ==Additional Resources== | ||
