Baldet P, Gerbling H, Axiotis S, Douce R
Unité mixte CNRS/Rhône-Poulenc (Associée au Centre National de la Recherche Scientifique, U.M.R. 41), Lyon, France.
Eur J Biochem. 1993 Oct 1;217(1):479-85. doi: 10.1111/j.1432-1033.1993.tb18267.x.
Biotin biosynthesis was investigated in lavender cell cultures (Lavandula vera L.). Two different biological assays and two different HPLC procedures were used to identify all the intermediates involved in biotin biosynthesis. The pathway for biotin biosynthesis could be analyzed starting with [3H]pimelic acid as precursor, leading to labelled biotin and even to labelled biotinylated enzymes. Intermediates known from the bacterial pathway (7-oxo-8-amino-pelargonic acid, 7,8-diamino-pelargonic acid, dethiobiotin) were present in detectable amounts. Pimelic acid activation to pimeloyl-CoA could be observed. In contrast to bacterial cells, an unknown stable labelled intermediate, named compound A, accumulated. This compound coeluted with an authentic sample of 9-mercaptodethiobiotin from HPLC with an anion-exchange column and was as effective as biotin in supporting the growth of the strain bioB105 of Escherichia coli. When 3H-labelled compound A was added to the growth medium of the lavender cells it was incorporated in an acidomycin-sensitive manner into biotin. [3H]Dethiobiotin was incorporated into both compound A and biotin. These results strongly suggest that, in higher plant cells, the reaction catalysed by biotin synthase may proceed in two distinct steps involving mercaptodethiobiotin (9-mercaptodethiobiotin?) as an intermediate.
对薰衣草细胞培养物（真薰衣草）中的生物素生物合成进行了研究。采用两种不同的生物测定法和两种不同的高效液相色谱法来鉴定生物素生物合成过程中涉及的所有中间体。生物素生物合成途径可以从以[3H]庚二酸为前体开始分析，生成标记的生物素，甚至生成标记的生物素化酶。细菌途径中已知的中间体（7-氧代-8-氨基壬酸、7,8-二氨基壬酸、脱硫生物素）以可检测的量存在。可以观察到庚二酸被激活生成庚二酰辅酶A。与细菌细胞不同，一种未知的稳定标记中间体，命名为化合物A，积累了下来。该化合物在阴离子交换柱高效液相色谱中与9-巯基脱硫生物素的真实样品共洗脱，并且在支持大肠杆菌生物B105菌株生长方面与生物素一样有效。当将3H标记的化合物A添加到薰衣草细胞的生长培养基中时，它以对放线菌素敏感的方式掺入生物素中。[3H]脱硫生物素被掺入化合物A和生物素中。这些结果有力地表明，在高等植物细胞中由生物素合酶催化的反应可能分两个不同步骤进行，涉及巯基脱硫生物素（9-巯基脱硫生物素？）作为中间体。
