Fructose Bisphosphate Aldolase: Difference between revisions
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The aldolase catalyzes the reversible cleavage of fructose-1,6-bisphosphate into dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (GAP). It can also catalyze the cleavage of fructose 1-phosphate to diydroxyacetone and glyceraldehyde (GA). Different isozymes exhibit preferences for either or both of the substrates, depending on the role of the aldolase (i.e. gluconeogenesis versus glycolysis).<ref name="book">Voet, D, Voet, J, & Pratt, C. (2008). Fundamentals of biochemistry, third edition. Hoboken, NJ: Wiley & Sons, Inc.</ref> | The aldolase catalyzes the reversible cleavage of fructose-1,6-bisphosphate into dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (GAP). It can also catalyze the cleavage of fructose 1-phosphate to diydroxyacetone and glyceraldehyde (GA). Different isozymes exhibit preferences for either or both of the substrates, depending on the role of the aldolase (i.e. gluconeogenesis versus glycolysis).<ref name="book">Voet, D, Voet, J, & Pratt, C. (2008). Fundamentals of biochemistry, third edition. Hoboken, NJ: Wiley & Sons, Inc.</ref> | ||
While it can exist as a monomer, it normally exists as a <scene name='Austin_Drake_Sandbox/Tetramer/3'>homotetramer</scene>. The enzyme is an a/B protein with a TIM beta/alpha beta fold. The fold designation is based upon the nine alpha helices and eight parallel beta sheets in a closed barrel of each monomeric subunit. It is part of the aldolase superfamily and the class I aldolases.<ref>Protein: fructose-1,6-bisphosphate aldolase from human (homo sapiens), muscle isozyme. (2009). Retrieved from http://scop.mrc-lmb.cam.ac.uk</ref><scene name='Austin_Drake_Sandbox/Different_colors/3'> | While it can exist as a monomer, it normally exists as a <scene name='Austin_Drake_Sandbox/Tetramer/3'>homotetramer</scene>. The enzyme is an a/B protein with a TIM beta/alpha beta fold. The fold designation is based upon the nine alpha helices and eight parallel beta sheets in a closed barrel of each monomeric subunit. It is part of the aldolase superfamily and the class I aldolases.<ref>Protein: fructose-1,6-bisphosphate aldolase from human (homo sapiens), muscle isozyme. (2009). Retrieved from http://scop.mrc-lmb.cam.ac.uk</ref> <scene name='Austin_Drake_Sandbox/Different_colors/3'>α helices and β sheets</scene> can be seen in their specific regions mostly concentric to the active site, represented by the blue and red residues. | ||
Although some form of fructose bisphosphate aldolase is present in nearly all living things, certain isoforms carry a large degree of conservation. The enzyme from rabbit muscle has nearly the tertiary and primary structure as the enzyme in human muscle. As a result, implications from rabbit muscle aldolase also reveal a great deal about the human forms of the enzyme. <ref name="review">Gefflaut, T., B. Casimir, J. Perie, and M. Willson. "Class I Aldolases: Substrate Specificity, Mechanism, Inhibitors and Structural Aspects." Prog. Biophys. molec. Biol.. 63. (1995): 301-340.</ref> | Although some form of fructose bisphosphate aldolase is present in nearly all living things, certain isoforms carry a large degree of conservation. The enzyme from rabbit muscle has nearly the tertiary and primary structure as the enzyme in human muscle. As a result, implications from rabbit muscle aldolase also reveal a great deal about the human forms of the enzyme. <ref name="review">Gefflaut, T., B. Casimir, J. Perie, and M. Willson. "Class I Aldolases: Substrate Specificity, Mechanism, Inhibitors and Structural Aspects." Prog. Biophys. molec. Biol.. 63. (1995): 301-340.</ref> | ||
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'''Kinetics''' | '''Kinetics''' | ||
Isotopic labelling has revealed the rate-determining step for the reaction. Either the carbon-carbon bond cleavage or the release of glyceraldehyde-3-phosphate comprise the slow step of the catalysis reaction; however, studies do indicate that the GAP release is likely the slowest step | Isotopic labelling has revealed the rate-determining step for the reaction. Either the carbon-carbon bond cleavage or the release of glyceraldehyde-3-phosphate comprise the slow step of the catalysis reaction; however, studies do indicate that the GAP release is likely the slowest step.<ref name="review" /> | ||
'''Regulation''' | '''Regulation''' | ||