4 Hydroxybenzoate geranyltransferase

4-hydroxybenzoate geranyltransferase (EC 2.5.1.93, PGT1, PGT2, 4HB geranyltransferase, 4HB:geranyltransferase, p-hydroxybenzoate geranyltransferase, PHB geranyltransferase, geranyl diphosphate:4-hydroxybenzoate geranyltransferase) is an enzyme with systematic name geranyl-diphosphate:4-hydroxybenzoate 3-geranyltransferase. This enzyme catalyses the following chemical reaction

geranyl diphosphate + 4-hydroxybenzoate ⇌ 3-geranyl-4-hydroxybenzoate + diphosphate

The enzyme is involved in shikonin biosynthesis. It has a strict substrate specificity for geranyl diphosphate and an absolute requirement for Mg²⁺.