Oxidoreductase; part of the gene cluster that mediates the biosynthesis of the diterpene ent-pimara-8(14),15-diene (PD) (PubMed:22506079, PubMed:27098256). Within the cluster, the HMG-CoA reductase AN1593 functions in the mevalonate pathway, which produces isoprenoid precursors (PubMed:22506079, PubMed:27098256). The geranylgeranyl pyrophosphate (GGPP) synthase AN1592 is needed in the formation of GGPP, the precursor for diterpenes (PubMed:22506079, PubMed:27098256). Lastly, the pimaradiene synthase pbcA performs the 2 cyclization steps that convert GGPP to ent-pimara-8(14),15-diene (PubMed:22506079, PubMed:27098256). The putative roles of the remaining cluster enzymes in ent-pimara-8(14),15-diene biosynthesis is unclear (Probable). The cytochrome P450 monooxygenase AN1598, the glutathione S-transferase AN1595, the oxidoreductases AN1596 and AN1597 probably function as decorative enzymes (Probable). It is possible that in biological conditions the compound is oxidized to ent-pimara-8(14),15-dien-19-oic acid, which is a bioactive diterpene compound predominant in many plant extracts (Probable). Secondary metabolite biosynthesis; terpenoid biosynthesis. Expression is positively regulated by the cluster-specific transcription factor pbcR. Belongs to the asaB hydroxylase/desaturase family.