Geranyltransferase

Geranyltransferase is an enzyme that catalyzes the transfer of a geranyl group, a 10-carbon isoprenoid moiety, to a substrate molecule. These enzymes are involved in a variety of biological processes, including the synthesis of secondary metabolites, protein modification, and signaling pathways. There are different types of geranyltransferases, often classified by the specific substrate they act upon or the donor molecule they utilize.

One important class is protein geranyltransferases, which attach geranyl groups to specific cysteine residues in proteins. This prenylation process is crucial for the localization and function of many proteins, particularly small GTPases that play roles in cell signaling. Farnesyltransferase and geranylgeranyltransferase are related enzymes that transfer different isoprenoid chains, farnesyl (15 carbons) and geranylgeranyl (20 carbons) respectively, but they share mechanistic similarities with geranyltransferases.

In plants and microorganisms, geranyltransferases are key enzymes in the biosynthesis of terpenoids. These compounds have diverse functions, from fragrances and pigments to medicinal properties. For instance, geranyltransferases can prenylate phenolic compounds, a step in the production of certain flavonoids and coumarins. The specific geranyltransferase involved determines which substrate is prenylated and influences the final structure of the isoprenoid-modified product. Research into geranyltransferases continues to uncover their diverse roles in cellular biochemistry and their potential as targets for therapeutic intervention.