What is the function of citrate lyase?
The Citrate Lyase (ACL) is the main cytosolic enzyme that converts the citrate exported from mitochondria by the SLC25A1 carrier in Acetyl Coenzyme A (acetyl-CoA) and oxaloacetate. Acetyl-CoA is a high-energy intermediate common to a large number of metabolic processes including protein acetylation reactions.
Is citrate synthase a ligase?
This enzyme belongs to the family of ligases, specifically those forming carbon-sulfur bonds as acid-thiol ligases. The systematic name of this enzyme class is citrate:CoA ligase (ADP-forming). Other names in common use include citryl-CoA synthetase, citrate:CoA ligase, and citrate thiokinase.
What are two products of citrate lyase?
It catalyzes the formation of acetyl-CoA and oxaloacetate from citrate and CoA with a concomitant hydrolysis of ATP to ADP and phosphate. One of these products, acetyl-CoA, serves several important biosynthetic pathways, including lipogenesis and cholesterogenesis.
Which enzyme take place in citrate metabolism?
Citrate synthase catalyzes the condensation reaction of the two-carbon acetate residue from acetyl coenzyme A and a molecule of four-carbon oxaloacetate to form the six-carbon citrate: acetyl-CoA + oxaloacetate + H2O → citrate + CoA-SH.
What converts citrate to acetyl?
enzyme ATP-citrate lyase
In the cytosol, the initial step of de novo lipid biogenesis consists in conversion of citrate to acetyl-CoA and oxaloacetate by the enzyme ATP-citrate lyase using the energy of ATP hydrolysis [59]. Cytosolic/nuclear acetyl-CoA is also produced by two acetyl-CoA synthetase enzymes that condense acetate and thiol.
What is adenosine triphosphate citrate lyase?
Adenosine triphosphate (ATP) citrate lyase (ACL) is a cytosolic enzyme most highly expressed in lipogenic tissues such as liver and white adipose tissue. 12. ACL catalyzes a reaction in which 2 carbons from citrate are transferred to CoA, with consumption of 1 ATP molecule and generation of acetyl CoA and oxaloacetate.
How does citrate regulate citrate synthase?
Citrate synthase is responsible for the rate of reaction in the first step of the cycle when the acetyl-CoA is combined with oxaloacetic acid to form citrate. It regulates the speed at which the citrate isomer isocitrate loses a carbon to form the five-carbon molecule α-ketoglutarate.
What does citrate synthase produce?
Citrate synthase is a protein with 433 amino acids with various functional groups that can react with substrates. This enzyme catalyzes oxaloacetate to eventually produce citrate as part of the citric acid (Krebs) cycle.
Does insulin activate citrate lyase?
Our findings indicate that insulin causes a 2- to 3-fold increment in the 3’P content of ATP-citrate lyase in 3’P- labeled hepatocytes, and a 45% increase in the content of alkali-labile phosphate in the purified enzyme; this represents an increase of 0.4 to 0.6 mol of P/mol of lyase holoenzyme.
How is citrate lyase regulated?
Thus, human ATP:citrate lyase activity is regulated in vitro allosterically by phosphorylated sugars as well as covalently by phosphorylation.
What is the role of citrate in metabolism?
Citrate links many important cellular processes, bridging carbohydrate and fatty acid metabolism and protein modification. Its role in producing acetyl-CoA for the acetylation of histones may turn out to be its most striking role in regulating immune cell function.
What enzymes does citrate regulate?
Citrate is synthesized inside the mitochondria by citrate synthase from acetyl-CoA and OAA. It is exported outside the mitochondria by CIC. Citrate inhibits PFK1, PK, PDH, and SDH.