4-Hydroxybenzoate geranyltransferase

{{Short description|Class of enzymes}}

{{Infobox enzyme

| Name = 4-hydroxybenzoate geranyltransferase

| EC_number = 2.5.1.93

| CAS_number =

| GO_code =

| image =

| width =

| caption =

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4-hydroxybenzoate geranyltransferase ({{EC number|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.{{cite journal | vauthors = Ohara K, Muroya A, Fukushima N, Yazaki K | title = Functional characterization of LePGT1, a membrane-bound prenyltransferase involved in the geranylation of p-hydroxybenzoic acid | journal = The Biochemical Journal | volume = 421 | issue = 2 | pages = 231–41 | date = June 2009 | pmid = 19392660 | doi = 10.1042/bj20081968 }}{{cite journal | vauthors = Mühlenweg A, Melzer M, Li SM, Heide L | title = 4-Hydroxybenzoate 3-geranyltransferase from Lithospermum erythrorhizon: purification of a plant membrane-bound prenyltransferase | journal = Planta | volume = 205 | issue = 3 | pages = 407–13 | date = July 1998 | pmid = 9640665 | doi = 10.1007/s004250050337 }}{{cite journal | vauthors = Yazaki K, Kunihisa M, Fujisaki T, Sato F | title = Geranyl diphosphate:4-hydroxybenzoate geranyltransferase from Lithospermum erythrorhizon. Cloning and characterization of a ket enzyme in shikonin biosynthesis | journal = The Journal of Biological Chemistry | volume = 277 | issue = 8 | pages = 6240–6 | date = February 2002 | pmid = 11744717 | doi = 10.1074/jbc.m106387200 | doi-access = free }} This enzyme catalyses the following chemical reaction

: geranyl diphosphate + 4-hydroxybenzoate $\backslash rightleftharpoons$ 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⁺.