Pyruvate kinase

 

Pyruvate kinase (PK) catalyzes the final reaction of glycolysis, the conversion of phosphoenol pyruvate to pyruvate, which is coupled to the formation of ATP.  This reaction is irreversible in cells.

 

 

from Matthews, Van Holde, and Ahern; Biochemistry, 3rd edition

 

Activator

Inhibitors

 

Fructose-1,6-bisphosphate

ATP

Alanine

Acetyl-CoA

 

Hormonal Control of PK

PK in the liver is sensitive to carbohydrate ingestion.  Glucagon causes the phosphorylation of PK, which renders it much less active.  Insulin diminishes this effect, and increases the concentration of the dephosphorylated, more active enzyme.

 

 

Structure of PK

From Structural Genetic Consortium:

http://sgc.utoronto.ca/SGC-WebPages/StructureDescription/1ZJH.php

PK is made of 4 identical subunits.  To the left is the structure of PKM2, an isomer of PK found in human muscle.  A different isomer, pictured below, is found in the liver and erythrocytes.

University of Pavia, Protein Crystallography Group

http://www.unipv.it/biocry/structures.php has an interactive look at its structure