THE POTENTIAL ROLE OF FATTY-ACID INITIATION IN THE BIOSYNTHESIS OF THE FUNGAL AROMATIC POLYKETIDE AFLATOXIN B-1
THE POTENTIAL ROLE OF FATTY-ACID INITIATION IN THE BIOSYNTHESIS OF THE FUNGAL AROMATIC POLYKETIDE AFLATOXIN B-1
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DOI：
10.1139/v94-031
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发表时间：
1994-01-01
影响因子：
1.1
通讯作者：
TOWNSEND, CA
中科院分区：
文献类型：
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作者：
BROBST, SW;TOWNSEND, CA
该实验室早期的工作表明，[1- c -13]己酸盐完整地结合到黄曲霉毒素B-1生物合成的关键中间体——阿维芦苷(1)中。用等摩尔量的[1-C-13]丁酸盐、[1-C-13]-3-氧辛酸盐和[1-C-13]-5-氧己酸盐进行平行实验，没有检测到重同位素的特定掺入，但与[1-C-13]醋酸盐的背景掺入相当低。这些聚酮形成的潜在中间体中的三个被重新检查为相应的n -乙酰半胱胺（NAC）硫酯。[1-C-13]己酸的NAC硫酯的完整掺入率高达22%，而[1-C-13]-3-氧辛酸的NAC硫酯在等量给寄生曲霉（ATCC 24551）时，其完整掺入率接近5%。相反，[1-C-13]丁酸的NAC硫酯没有选择性富集阿维黄酮。在对[2,3- c -13(2)]丁酸的NAC硫酯更敏感的实验中，进一步验证了这一阴性结果。检测到No (1)J（CC）耦合，表明掺入效率为
Earlier work in this laboratory has shown the intact incorporation of [1-C-13]hexanoate into averufin (1), a key intermediate in aflatoxin B-1 biosynthesis. Parallel experiments with equimolar amounts of [1-C-13]butyrate, [1-C-13]-3-oxo-octanoate, and [1-C-13]-5-oxo-hexanoate gave no detectable specific incorporation of heavy isotope but low and equivalent background incorporation comparable to [1-C-13]acetate. Three of these potential intermediates in polyketide formation were reexamined as their corresponding N-acetylcysteamine (NAC) thioesters. The NAC thioester of [1-C-13]hexanoic acid gave a remarkably high 22% intact incorporation while the NAC thioester of [1-C-13]-3-oxo-octanoic acid afforded nearly 5% when an equimolar amount was administered to the producing organism Aspergillus parasiticus (ATCC 24551). In contrast, the NAC thioester of [1-C-13]butyric acid showed no selective enrichment of averufin. This negative result was tested further in a more sensitive experiment with the NAC thioester of [2,3-C-13(2)]butyric acid. No (1)J(CC) coupling was detectable, indicating an incorporation efficiency of