All-trans-phytoene synthase

All-trans-phytoene synthase (, prephytoene-diphosphate synthase, phytoene synthetase, PSase, geranylgeranyl-diphosphate geranylgeranyltransferase, 15-trans-phytoene synthase) is an enzyme with systematic name geranylgeranyl-diphosphate:geranylgeranyl-diphosphate geranylgeranyltransferase (all-trans-phytoene forming). This enzyme catalyses the following chemical reaction


 * 2 geranylgeranyl diphosphate $$\rightleftharpoons$$ all-trans-phytoene + 2 diphosphate (overall reaction)
 * (1a) 2 geranylgeranyl diphosphate $$\rightleftharpoons$$ diphosphate + prephytoene diphosphate
 * (1b) prephytoene diphosphate $$\rightleftharpoons$$ all-trans-phytoene + diphosphate

This enzyme requires Mn2+ for activity.