Trifunctional enzyme subunit beta, mitochondrial (TP-beta) also known as 3-ketoacyl-CoA thiolase, acetyl-CoA acyltransferase, or beta-ketothiolase is an enzyme

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 that in humans is encoded by the HADHB gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

.

HADHB is a subunit of the mitochondrial trifunctional protein

Mitochondrial trifunctional protein

Mitochondrial trifunctional protein is a protein which catalyzes several reactions in beta oxidation. It has two subunits:* HADHA* HADHBThe three functions are long-chain 3-hydroxy acyl-coenzyme A dehydrogenase, 2-enoyl coenzyme A hydratase, and long-chain 3-ketoacyl CoA...

 and has thiolase

Thiolase

Thiolases also known as acetyl-Coenzyme A acetyltransferases are enzymes which converts two units of acetyl-CoA to acetoacetyl CoA in the mevalonate pathway....

activity.

Function

This gene encodes the beta subunit of the mitochondrial trifunctional protein, which catalyzes the last three steps of mitochondrial beta-oxidation of long chain fatty acids. The mitochondrial membrane-bound heterocomplex is composed of four alpha and four beta subunits, with the beta subunit catalyzing the 3-ketoacyl-CoA thiolase activity. Mutations in this gene result in trifunctional protein deficiency. The encoded protein can also bind RNA and decreases the stability of some mRNAs. The genes of the alpha and beta subunits of the mitochondrial trifunctional protein are located adjacent to each other in the human genome in a head-to-head orientation.

External links