dekarboxylas

Decarboxylases, or dekarboxylases, are enzymes that remove carboxyl groups from substrates, releasing carbon dioxide. They are classified as lyases (EC 4.1) and play important roles in amino acid metabolism, neurotransmitter biosynthesis, and microbial adaptations. Decarboxylases act in organisms ranging from bacteria to humans and can influence processes such as acid resistance, signaling, and energy production.

Most well-known decarboxylases are pyridoxal phosphate (PLP)–dependent enzymes. They typically convert an amino acid into an amine, for example turning tyrosine into tyramine or glutamate into GABA. Other decarboxylases use different cofactors; pyruvate decarboxylase, for instance, relies on thiamine pyrophosphate (TPP) to remove CO2 from pyruvate, yielding acetaldehyde in yeast and related microbes. Some decarboxylases act on non-amino acid substrates, such as oxaloacetate decarboxylase, which participates in metabolic and membrane transport processes in certain bacteria.

Key examples include aromatic L-amino acid decarboxylases (such as DOPA decarboxylase, which converts L-DOPA to dopamine), glutamate decarboxylase (producing GABA in the nervous system and in bacterial GAD systems that aid acid resistance), and histidine decarboxylase (producing histamine). Structural architectures vary, but many PLP-dependent decarboxylases form homodimers or higher-order oligomers and share conserved cofactor-binding motifs.

In biology, decarboxylases influence neurotransmitter levels, metabolic fluxes, and microbial adaptation to environmental stress. They are also studied for biotechnological applications, including the biosynthesis of amines and the production of commodity chemicals.