Involved in gibberellin (GA) biosynthesis. Catalyzes three successive oxidations of ent-kaurenoic acid giving gibberellin 12 (GA12), a key step in GAs biosynthesis. GAs, which are involved many processes, including stem elongation, play a central role in plant development (Probable). Required for pollen germination and elongation (PubMed:18083909). ent-kaur-16-en-19-oate + 3 O2 + 3 reduced [NADPH--hemoprotein reductase] = gibberellin A12 + 4 H(+) + 4 H2O + 3 oxidized [NADPH--hemoprotein reductase] Plant hormone biosynthesis; gibberellin biosynthesis. Expressed in roots and panicles. Expressed at low levels in vegetative shoot apices, leaf sheaths, leaf blades and stems. Severe dwarf phenotype without flower or seed development. Belongs to the cytochrome P450 family.