Novel tryptophan metabolic pathways in auxin biosynthesis in silkworm
Novel tryptophan metabolic pathways in auxin biosynthesis in silkworm
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DOI：
10.1016/j.jinsphys.2017.07.006
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发表时间：
2017-08-01
影响因子：
2.2
通讯作者：
Suzuki, Yoshihito
中科院分区：
文献类型：
--
作者：
Yokoyama, Chiaki;Takei, Mami;Suzuki, Yoshihito
在研究植物激素生长素的生物合成途径的过程中，我们提出了色氨酸(Trp)->；吲哚-3-乙醛肟(IAOx)->；吲哚-3-乙醛(IAA1d)->；吲哚-3-乙酸(IAA)的生物合成途径。在本研究中，我们确定了家蚕体内代谢途径中可能影响IAA产生效率的两个分支：色氨酸吲哚-3-丙酮酸->；吲哚-3-乳酸和IAAeld->；吲哚-3-乙醇。我们还测定了表观转化活性(Trp-&Gt；IAA为2.05×10(-7)uml(-1)，IAOx->；IAA为1.30×10(-5)UmL(-1)，IAAeld->；IAA为3.91×10(-1)UmL(-1))，这解释了为什么IAOx和IAAeld作为其前体的内源化合物或代谢物几乎检测不到。即使在存在IAAd->IAA转换抑制剂的情况下也未能检测到IAAd，这是由于从IAAd->IAA到IAAd->IEtOH的转换过程中发生了切换。
In the course of our study of the biosynthetic pathway of auxin, a class of phytohormones, in insects, we proposed the biosynthetic pathway tryptophan (Trp) -> indole-3-acetaldoxime (IAOx) -> indole-3-acetadehyde (IAA1d) -> indole-3-acetic acid (IAA). In this study, we identified two branches in the metabolic pathways in the silkworm, possibly affecting the efficiency of IAA production: Trp indole-3-pyruvic acid -> indole-3-lactic acid and IAAld -> indole-3-ethanol. We also determined the apparent conversion activities (2.05 x 10(-7) UmL(-1) for Trp -> IAA, 1.30 x 10(-5) U mL(-1) for IAOx -> IAA, and 3.91 x 10(-1) U mL(-1) for IAAld -> IAA), which explain why IAOx and IAAld are barely detectable as either endogenous compounds or metabolites of their precursors. The failure to detect IAAld, even in the presence of an inhibitor of the conversion IAAld -> IAA, is explained by a switch in the conversion from IAAld -> IAA to IAAld -> IEtOH.