Limonene synthase (LS)

Limonene synthase is a key plant enzyme responsible for the biosynthesis of the monoterpene limonene from geranyl pyrophosphate (GPP). This enzyme exists in two enantiomeric forms: (S)-limonene synthase (EC 4.2.3.16), which produces (-)-limonene found in peppermint and spearmint, and (R)-limonene synthase (EC 4.2.3.20), which produces (+)-limonene characteristic of citrus fruits. Biologically, the enzyme plays a crucial role in plant defense mechanisms, producing volatile compounds that can deter herbivores or attract pollinators. While limonene itself is studied for potential anticancer and anti-inflammatory properties, the enzyme is not a recognized therapeutic target in human disease. Instead, it is a major focus in metabolic engineering and synthetic biology for the industrial production of limonene, which is used extensively in fragrances, flavoring agents, and as a renewable solvent or biofuel precursor (Croteau et al., 1987; UniProt P14714).

Other names

(S)-limonene synthase(R)-limonene synthase4S-limonene synthase4R-limonene synthaseGeranyl-diphosphate cyclizingl-limonene synthased-limonene synthase

Catalyzes the cyclization of geranyl pyrophosphate (GPP) into limonene through a carbocation-mediated mechanism involving the loss of a pyrophosphate group and subsequent ring closure.