Tiolase

Tiolase is a term that can refer to a few different biochemical entities, primarily enzymes. The most common context for "tiolase" is in relation to enzymes that cleave thioester bonds. These enzymes are crucial in various metabolic pathways.

One notable example is 3-oxoacyl-ACP thiolase, also known as acetoacetyl-CoA thiolase. This enzyme catalyzes the reversible cleavage of acetoacetyl-CoA into two molecules of acetyl-CoA. This reaction is a key step in both fatty acid synthesis and fatty acid degradation (beta-oxidation). In fatty acid synthesis, it condenses acetyl-CoA units, while in degradation, it breaks down fatty acids.

Another enzyme sometimes referred to as a tiolase is thiolase I, which is involved in the breakdown of branched-chain amino acids. This enzyme participates in the catabolism of leucine, isoleucine, and valine. It plays a role in generating acetyl-CoA and succinyl-CoA from these amino acids. The specific substrate and products can vary depending on the organism and the precise enzyme.

The term "tiolase" specifically highlights the enzyme's ability to interact with or cleave thioester linkages, which are characterized by a sulfur atom bonded to a carbonyl group. These enzymes are vital for energy metabolism and the synthesis of important biomolecules.