Pyruvate Kinase M Type

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Contents 1 More Specific Terms 2 Function 3 Structure 4 Alternative-splicing 5 Expression 6 Genetics 7 Notes 8 More General Terms 9 Internet Database 10 References

More Specific Terms

• pyruvate kinase M1 [muscle] (cytosolic thyroid hormone-binding protein)
• pyruvate kinase M2 (PKM2)

Function

• glycolytic enzyme that catalyzes the transfer of a phosphoryl group from phosphoenolpyruvate ( PEP) to ADP, generating ATP
• isoform M2 is allosterically activated by D- fructose 1,6-biphosphate ( FBP)
• carbohydrate degradation; glycolysis pyruvate from D- glyceraldehyde 3- phosphate: step 5/5
• phosphorylated upon DNA damage, probably by ATM or ATR
  

• ATP + pyruvate <--> ADP + phosphoenolpyruvate
  Cofactors: Mg+2, K+
  
• Kinetic parameters:

• KM=2.7 mM for phosphoenolpyruvate#
• KM=0.17 mM for phosphoenolpyruvate (in the presence of 2mM FBP)
• KM=0.34 mM for ADP
• KM=0.24 mM for ADP (in the presence of 2mM FBP)
  

• # at pH=8 & 32 degrees celsius
  
• inhibited by oxalate

Structure

• homotetramer belongs to the pyruvate kinase family

Alternative-splicing

• named isoforms=2

Expression

• early fetal tissues as well as in most cancer cells

Genetics

• M1 & M2 isoforms from same gene, by alternative splicing

Notes

• 4 isozymes of pyruvate kinase in mammals: L, R, M1 & M2
• L type is major isozyme in the liver
• R is found in red cells
• M1 is the main form in muscle, heart & brain
• M2 is found in early fetal tissues as well as in most cancer cells

More General Terms

• pyruvate kinase

Internet Database

UniProt: [1]
Kegg: [2]
OMIM: 179050
Prosite: [3]

References

1. UniProt [4]
2. Wikipedia; Note: pyruvate kinase entry [5]
3. Stryer Biochemistry WH Freeman & Co, New York,1988 pg 362
4. Wikipedia; Note: pyruvate kinase entry [6]

pyruvate kinase M-type