Photorespiratory Hydroxypyruvate Metabolism in Arabidopsis

大多数陆地植物，在光呼吸C2循环中，每天产生大量的3-羟丙酮酸（3HP）。科学文献一致认为，这些大量的3HP仅由过氧化物酶体酶NADH:3HP还原酶（HPR1）代谢。与目前的共识相反，我们在对拟南芥HPR1基因敲除植物的初步研究中表明，存在另一条具有显著能力的3HP代谢途径。该项目试图确定参与植物初级代谢这一未知途径的酶、基因和代谢物。这将通过生物化学和遗传学相结合的方法来实现，包括蛋白质纯化和表征，双突变体和三突变体的产生，代谢通量和详细的代谢组分析，以及定量评估全叶的气体交换参数。

Most land plants, in the photorespiratory C2 cycle, produce very large daily amounts of 3-hydroxypyruvate (3HP). There is agreement in the scientific literature that these large amounts of 3HP are exclusively metabolized by the peroxisomal enzyme NADH:3HP reductase (HPR1). In contrast to this current consensus, we have shown in preliminary studies with Arabidopsis HPR1 knockout plants the existence of an additional 3HP metabolizing pathway of remarkable capacity. The project attempts to identify the enzymes, genes, and metabolites which are involved in this yet unknown pathway of plant primary metabolism. This will be achieved by a combined biochemical and genetical approach including protein purification and characterization, generation of double and triple mutants, metabolic flux and detailed metabolome analyses, as well as by quantitatively assessing gas-exchange parameters of whole leaves.