LETHAL SYNTHESIS OF METHYLGLYOXAL BY ESCHERICHIA-COLI DURING UNREGULATED GLYCEROL METABOLISM
LETHAL SYNTHESIS OF METHYLGLYOXAL BY ESCHERICHIA-COLI DURING UNREGULATED GLYCEROL METABOLISM
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DOI：
10.1128/jb.108.1.137-144.1971
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发表时间：
1971-01-01
影响因子：
3.2
通讯作者：
LIN, ECC
中科院分区：
文献类型：
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作者：
FREEDBERG, WB;KISTLER, WS;LIN, ECC
在Escherichia coliK-12中，甘油转化为磷酸三糖受到两种控制机制的调节：甘油激酶的合成速率和1，6-二磷酸果糖对其活性的反馈抑制。一个菌株通过连续的突变失去了这两种控制机制，导致甘油激酶的结构性合成不再对反馈抑制敏感，它可以从甘油中产生杀菌因子。这种毒性因子经化学和酶学试验鉴定为甲基乙二醛。甲基乙二醛可以通过酶的作用从磷酸二羟丙酮中得到，这种酶存在于突变株和野生型菌株的提取物中，具有很高的组成水平。已分离到9个抗1 mM外源甲基乙二醛的自发突变体。在所有情况下，抗药性都与谷胱甘肽依赖的酶活性增加有关，以去除甲基乙二醛。来自甘油敏感亲本菌株的甲基乙二醛抗性突变体也对甘油具有免疫力。
InEscherichia coliK-12, the conversion of glycerol to triose phosphate is regulated by two types of control mechanism: the rate of synthesis of glycerol kinase and the feedback inhibition of its activity by fructose-1,6-diphosphate. A strain which has lost both control mechanisms by successive mutations, resulting in the constitutive synthesis of a glycerol kinase no longer sensitive to feedback inhibition, can produce a bactericidal factor from glycerol. This toxic factor has been identified by chemical and enzymological tests as methylglyoxal. Methylglyoxal can be derived from dihydroxyacetone phosphate through the action of an enzyme which is present at high constitutive levels in the extracts of the mutant as well as that of the wild-type strain. Nine spontaneous mutants resistant to 1 mmexogenous methylglyoxal have been isolated. In all cases the resistance is associated with increased levels of a glutathione-dependent enzymatic activity for the removal of methylglyoxal. Methylglyoxal-resistant mutants derived from the glycerol-sensitive parental strain also became immune to glycerol.