LEVELS OF GLYCOGEN AND TREHALOSE IN MYCOBACTERIUM-SMEGMATIS AND PURIFICATION AND PROPERTIES OF GLYCOGEN SYNTHETASE
LEVELS OF GLYCOGEN AND TREHALOSE IN MYCOBACTERIUM-SMEGMATIS AND PURIFICATION AND PROPERTIES OF GLYCOGEN SYNTHETASE
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DOI：
10.1128/jb.113.2.863-873.1973
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发表时间：
1973-01-01
影响因子：
3.2
通讯作者：
MITCHELL, M
中科院分区：
文献类型：
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作者：
ELBEIN, AD;MITCHELL, M
比较了在不同氮限制条件下生长的耻垢分枝杆菌中糖原、游离海藻糖和脂质结合海藻糖的水平。在添加酵母提取物和果糖作为碳源的无机盐培养基中，随着培养基中NH4Cl含量的降低，糖原的积累急剧增加。然而，游离海藻糖的水平保持相对恒定。使细胞在低氮培养基中生长，然后转移到含有高氮的培养基中。在这些条件下，低氮时糖原迅速积累，而当细胞置于高氮培养基中时，糖原迅速耗尽。游离海藻糖的浓度同样保持相当恒定。然而，当细胞在含有[14 C]果糖的低氮培养基中生长，然后转移到含有未标记果糖的高氮培养基中时，游离海藻糖的比放射性（每分钟每微摩尔的计数）立即下降，表明它正在不断合成和周转。另一方面，糖原和结合海藻糖的比放射性下降得慢得多，表明这两种化合物的转化速度没有那么快，或者合成速度慢得多。[14 C]果糖掺入糖原和海藻糖的实验表明，高氮培养基中的细胞合成糖原比低氮培养基中的细胞少得多。然而，在两种情况下，游离海藻糖和结合海藻糖的合成是相同的。糖原合成酶和海藻糖磷酸合成酶的特定酶活性从一种生长条件到另一种生长条件略有不同，但酶活性与糖原或海藻糖的量之间没有相关性，表明糖原水平的变化不是由于合成能力增加。糖原合成酶纯化约35倍，并检查其性质。该酶对作为葡萄糖基供体的腺苷二磷酸葡萄糖具有特异性。
The levels of glycogen, free trehalose, and lipid-bound trehalose were compared inMycobacterium smegmatisgrown under various conditions of nitrogen limitation. In a mineral salts medium supplemented with yeast extract and containing fructose as the carbon source, the accumulation of glycogen increased dramatically as the NH4Cl content of the medium was lowered. However, levels of free trehalose remained relatively constant. Cells were grown in low nitrogen medium and were then shifted to medium containing high nitrogen. Under these conditions, there was a rapid accumulation of glycogen in low nitrogen, and this glycogen was rapidly depleted when cells were placed in high nitrogen medium. Again the concentration of free trehalose remained fairly constant. However, when cells were grown in low nitrogen medium with [14C]fructose and then transferred to high nitrogen medium with unlabeled fructose, the specific radioactivity (counts per minute per micromole) of the free trehalose fell immediately, indicating that it was being synthesized and turned over continually. On the other hand, the specific radioactivity of the glycogen and bound trehalose declined much more slowly, suggesting that these two compounds were not turning over as rapidly or were being synthesized at a much slower rate. Experiments on the incorporation of [14C]fructose into glycogen and trehalose indicated that cells in high nitrogen medium synthesized much less glycogen than those in low nitrogen. However, synthesis of both free trehalose and bound trehalose was the same in both cases. The specific enzymatic activities of the glycogen synthetase and the trehalose phosphate synthetase varied somewhat from one growth condition to another, but there was no correlation between enzymatic activity and the amount of glycogen or trehalose, suggesting that changes in glycogen levels were not due to increased synthetic capacity. The glycogen synthetase was purified about 35-fold and its properties were examined. This enzyme was specific for adenosine diphosphate glucose as the glucosyl donor.