Bisphosphoglycerate mutase
bisphosphoglycerate mutase | |||||||||
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ExPASy NiceZyme view | | ||||||||
KEGG | KEGG entry | ||||||||
MetaCyc | metabolic pathway | ||||||||
PRIAM | profile | ||||||||
PDB structures | RCSB PDB PDBe PDBsum | ||||||||
Gene Ontology | AmiGO / QuickGO | ||||||||
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2,3-bisphosphoglycerate mutase | |||||||
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Chr. 7 q31-q34 | |||||||
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Bisphosphoglycerate mutase (
Tissue distribution
Because the main function of bisphosphoglycerate mutase is the synthesis of 2,3-BPG, this enzyme is found only in
Function
1,3-BPG is formed as an intermediate in glycolysis. BPGM then takes this and converts it to 2,3-BPG, which serves an important function in oxygen transport. 2,3-BPG binds with high affinity to Hemoglobin, causing a conformational change that results in the release of oxygen. Local tissues can then pick up the free oxygen. This is also important in the placenta, where fetal and maternal blood come within such close proximity. With the placenta producing 2,3-BPG, a large amount of oxygen is released from nearby maternal hemoglobin, which can then dissociate and bind with fetal hemoglobin, which has a much lower affinity for 2,3-BPG.[2]
Structure
Overall
BPGM is a dimer composed of two identical protein subunits, each with its own active site. Each subunit consists six β-strands, β A-F, and ten α-helices, α 1–10.
Important residues
- His11: the nucleophile of the 1,2-BPG to 1,3-BPG reaction. Rotates back and forth with the help of His-188 to get in an in-line position in order to attack the 1’ phosphate group.[3]
- His-188: involved in overall stability of protein,[4] as well as hydrogen bonding to substrate, as His-11, which it pulls into its catalytic position.
- Arg90: although not involved directly in binding, this positively charged residue is essential to overall stability of the protein. Can be substituted with Lysine with little effect on catalysis.[4]
- Cys23: has little effect on overall structure, but large effect on reactivity of the enzyme.[5]
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2-3 Bisphosphoglycerate in the active site of Bisphosphoglycerate Mutase. Depicted and labeled are the residues that assist in holding the substrate in place: Arg10, Arg62, Arg100, Arg116, Arg117, His11, His188, Tyr92,Glu89.
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2-D depiction of all residues in active site that help hold the substrate in the proper position for mutation.[3]
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Mechanism for conversion of 1-3BPG to 2-3 BPG.[3]
Mechanism of catalysis
1,3-BPG binds to the
References
Further reading
- Fujita T, et al. (1 December 1998). "Human erythrocyte bisphosphoglycerate mutase: inactivation by glycation in vivo and in vitro". J Biochem. 124 (6): 1237–44. PMID 9832630.
External links
- Bisphosphoglycerate Mutase at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
- EC 5.4.2.4