ATP citrate lyase

ATP citrate lyase is an enzyme that represents an important step in fatty acid biosynthesis.

Function

ATP citrate lyase is the primary enzyme responsible for the synthesis of cytosolic acetyl-CoA in many tissues. The enzyme is a tetramer of apparently identical subunits. The product, acetyl-CoA, serves several important biosynthetic pathways, including lipogenesis and cholesterogenesis. It is activated in by insulin.

Reaction

In the presence of ATP and Coenzyme A, catalyzes the cleavage of citrate to yield acetyl CoA, oxaloacetate, ADP, and orthophosphate:

citrate + ATP + CoA-->oxaloacetate + Acetyl-CoA + ADP + Pi.

This enzyme was formerly listed as EC 4.1.3.8.

Location

The enzyme is cytosolic in plants and animals.

Structure

The enzyme is composed of two subunits in green plants (including Chlorophyceae, Marchantimorpha, Bryopsida, Pinaceae, monocotyledons, and eudicots), species of fungi, Glaucophytes, Chlamydomonas, and prokaryotes.

Animal ACL enzymes are homomeric, presumably an evolutionary fusion of the ACLA and ACLB genes probably occurred early in the evolutionary history of this kingdom.

References

External links