Benzylisoquinoline alkaloids (BIAs) are medicinal compounds that are the vital constituents of several pharmaceutical preparations, including vasodilator with papaverine. Though intermediate steps and associated enzymes involved in the biosynthesis of key BIAs of opium poppy have been characterized, very limited information is available for the biosynthesis of papaverine. Through various studies, two metabolic routes utilizing (S)-norcoclaurine as substrate for the biosynthesis of papaverine have been suggested. These two controversial pathways for papaverine biosynthesis (NH and NCH₃) include a short-chain dehydrogenase/reductase (SDR) that catalyzes dehydrogenation of tetrahydropapaverine to papaverine. In this work, we have identified and functionally characterized one SDR, PsDeHase, which might participate in the dehydrogenation in the papaverine biosynthesis. The expression analysis and metabolite profiling suggested a correlation between transcript and papaverine content. The PsDeHase expressed abundantly in stem and shared homology with reductases involved in the secondary metabolism. In silico investigation predicted tetrahydropapaverine as the possible substrate that formed a stable complex with PsDeHase. Repression of PsDeHase transcripts in opium poppy plants exposed to VIGS treatment led to a comparable decrease in the accumulation of papaverine.

苄基异喹啉生物碱（BIAs）是药用化合物，是几种药物制剂的重要成分，包括血管扩张药和罂粟碱。尽管已表征了罂粟关键BIA生物合成中涉及的中间步骤和相关酶，但罂粟碱的生物合成信息非常有限。通过各种研究，已经提出了两种利用（S）-去甲紫花碱为底物进行罂粟碱生物合成的代谢途径。罂粟碱生物合成的这两个有争议的途径（NH和NCH ₃）包括催化四氢罂粟碱脱氢为罂粟碱的短链脱氢酶/还原酶（SDR）。在这项工作中，我们已经确定了一种SDR PsDeHase并在功能上进行了表征，该SDR可能参与罂粟碱生物合成中的脱氢反应。表达分析和代谢产物分析表明，转录物和罂粟碱含量之间存在相关性。PsDeHase在茎中大量表达，并与参与次级代谢的还原酶具有同源性。在计算机研究中预测四氢罂粟碱可能与PsDeHase形成稳定的复合物。暴露于VIGS处理的罂粟植物中PsDeHase转录物的阻遏导致罂粟碱积累的下降。