Catabolic pathway for aerobic degradation of lactate by Actinomyces naeslundii.
Catabolic pathway for aerobic degradation of lactate by Actinomyces naeslundii.
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内氏放线菌有氧降解乳酸的分解代谢途径。
DOI：
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发表时间：
1996
影响因子：
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通讯作者：
T. Yamada
中科院分区：
文献类型：
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作者：
N. Takahashi;T. Yamada
研究了口腔放线菌对乳酸的有氧代谢。在有氧条件下，7株内氏放线菌中有6株在乳酸盐的存在下生长增加。在乳酸盐上生长的洗涤细胞有氧降解乳酸盐和丙酮酸盐为乙酸盐，伴随着氧的消耗。在过氧化氢酶的存在下，消耗的氧与产生的乙酸的摩尔比对于乳酸降解为1，对于丙酮酸降解为0.5。在细胞提取物中发现的酶活性显示，乳酸可以通过NAD非依赖性乳酸脱氢酶（iLDH）转化为丙酮酸，并进一步通过丙酮酸脱氢酶（PDH）转化为乙酰辅酶A。形成的乙酰辅酶A可被磷酸转乙酰酶（PTA）和乙酸激酶（AK）代谢为乙酸，形成ATP。这些结果表明A. Naeslundii通过iLDH、PDH、PTA和AK的连续酶促反应将乳酸代谢成乙酸，并且由iLDH和PDH产生的氢被转移成氧。乳酸降解和氧消耗的活性可以改变牙菌斑的环境条件。
The aerobic metabolism of lactate by oral Actinomyces was studied. Six of 7 strains of Actinomyces naeslundii increased their growth in the presence of lactate under aerobic conditions. Washed cells grown on lactate aerobically degraded lactate and pyruvate to acetate with a concomitant consumption of oxygen. In the presence of catalase, the molar ratios of oxygen consumed to acetate produced were 1 for lactate degradation and 0.5 for pyruvate degradation. The enzymatic activities found in cell extracts revealed that lactate could be converted to pyruvate by NAD-independent lactate dehydrogenase (iLDH) and further to acetyl CoA by pyruvate dehydrogenase (PDH). The acetyl CoA formed could be metabolized into acetate by phosphotransacetylase (PTA) and acetate kinase (AK) with the formation of ATP. These results indicate that A. naeslundii metabolizes lactate into acetate by the sequential enzymatic reactions iLDH, PDH, PTA and AK and that hydrogens produced by iLDH and PDH are transferred to oxygen. The activity of lactate degradation and oxygen consumption may modify the environmental conditions of dental plaque.
碳酸氢盐对粘性放线菌糖酵解的刺激作用及其生化机制。
影响因子：
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作者：
Takahashi,N;Yamada,T
通讯作者：
Yamada,T