EFFECT OF BIOTIN ON BACTERIAL FORMATION OF GLUTAMIC ACID .1. GLUTAMATE FORMATION AND CELLULAR PERMEABILITY OF AMINO ACIDS
EFFECT OF BIOTIN ON BACTERIAL FORMATION OF GLUTAMIC ACID .1. GLUTAMATE FORMATION AND CELLULAR PERMEABILITY OF AMINO ACIDS
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DOI：
10.1093/oxfordjournals.jbchem.a127500
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发表时间：
1962-01-01
影响因子：
2.7
通讯作者：
TAKAHASHI, M
中科院分区：
文献类型：
--
作者：
SHIIO, I;OTSUKA, S;TAKAHASHI, M
当黄色短背藻No. 2247在富含生物素的培养基中生长，在洗涤的细胞和生长培养物中，L-谷氨酸不是由葡萄糖或乙酸形成的，而当该细菌在缺乏生物素的培养基中生长时，L-谷氨酸在洗涤的细胞和生长培养物中形成。虽然无细胞提取物的L-天冬氨酸-α-酮戊二酸转氨酶活性不受培养基中生物素浓度的影响，但洗涤的细胞的L-天冬氨酸-α-酮戊二酸转氨酶活性受到很大影响，并且，也就是说，在富含生物素的培养基中生长的洗涤后的细胞的活性小到可以忽略不计，而通过用去污剂物质处理细胞来恢复其活性。生物素对转氨酶活性以及洗涤细胞的谷氨酸形成能力的影响取决于细胞生长的碳源。在缺乏生物素的培养基中生长的细胞中的细胞内氨基酸的量少于在富含生物素的培养基中生长的细胞中的细胞内氨基酸的量。在前一种情况下，细胞在用缓冲溶液洗涤后几乎完全释放出细胞内氨基酸，但在后一种情况下则不然，只有当细胞与洗涤剂物质一起孵育时才能观察到这些氨基酸的释放。当细胞与氨基酸和α-酮戊二酸一起孵育时，在缺乏生物素的培养基中生长的细胞中观察到细胞内的净掺入，但在富含生物素的培养基中生长的细胞中观察不到。从这些结果可以看出，生物素对代谢的主要影响之一细胞的能力似乎存在于细胞对氨基酸的通透性中，这也可以解释对细胞谷氨酸形成能力的影响。
WhenBrevibackrium flavumNo. 2247 grew in a biotin-rich medium, L-glutamate was not formed from glucose nor acetate in the washed cells as well as in the growing culture, whereas it was formed in the washed cells as well as in the growing culture when this bacterium grew in a biotin-poor medium.Although L-aspartic-α-ketoglutaric transaminase activity of cell-free extracts was not affected by the biotin concentration in the culture medium, that of the washed cells was greatly affected and, that is, the activity of the washed cells grown in a biotin-rich medium was ncgligibly small while it was recovered by treating the cells with the detcrgent substances. The effect of biotin on the transaminase activity as well as on the glutamate forming ability of the washed cells depended on the carbon source on which the cells had grown.The amount of the intracellular amino acids in the cells grown in a biotin-poor medium was less than that in the cells grown in a biotin-rich medium. In the former case, the cells released the intracellular amino acids almost completely upon washing with a buffer solution, but not in the latter case, where the release of those was observed only when the cells were incubated with detergent substances.When the cells were incubated with amino acids and with a-ketoglutaric acid, net incorporation into the cells was observed in the cells grown in a biotin-poor medium but not in the cells grown in a biotin-rich medium.From these results, one of the main effects of biotin on the metabolic ability of the cells seems to exist in the cellular per meability of amino acids and it can also explain the effect on the glutamate forming ability of the cells.