Lysine biosynthesis in the yeast Candida maltosa: properties of some enzymes and regulation of the biosynthetic pathway
Lysine biosynthesis in the yeast Candida maltosa: properties of some enzymes and regulation of the biosynthetic pathway
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麦芽糖酵母中的赖氨酸生物合成：一些酶的特性和生物合成途径的调节
DOI：
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发表时间：
1985
期刊：
影响因子：
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通讯作者：
D. Birnbaum
中科院分区：
文献类型：
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作者：
H. Schmidt;R. Bode;M. Lindner;D. Birnbaum
对麦芽糖假丝酵母赖氨酸生物合成途径的4种酶进行了研究，并建立了其调控模式。α‐氨基二酸还原酶（Mr . 160000）、糖精还原酶（Mr . 90000）和糖精脱氢酶（Mr . 45000）相互分离。高柠檬酸合酶对所采用的分离方法敏感。糖精还原酶的形成是组成性的，而高柠檬酸合成酶、α‐氨基己二酸还原酶和糖精脱氢酶的合成则受氨基酸生物合成总控制的调控。l‐赖氨酸（Ki = 5.0 mm）、l‐硫赖氨酸（Ki = 15 mm）和dl‐α‐氨基己二酸酯（Ki = 5.1 mm）抑制高柠檬酸合成酶，这是该途径的第一个酶。对2‐氧葡萄糖酸盐的抑制是竞争性的。乙酰辅酶a的Km值估计为0.033 mm， 2 -氧葡萄糖酸酯的Km值估计为0.025 mm。α‐氨基己二酸还原酶的Michaelis常数计算为α‐氨基己二酸还原酶为0.20 mm， ATP为0.50 mm， NADPH为0.10 mm， MgCl2为3.8 mm。糖精还原酶的Km‐值分别为糖精还原酶0.55 mm和NADP+还原酶0.13 mm。糖精脱氢酶的值估计赖氨酸为1.6 mm，二氧葡萄糖酸为0.66 mm， NADH为0.23 mm。此外，一些氨基酸被发现是酶反应的效应器。
Four enzymes of the lysine biosynthetic pathway of Candida maltosa were investigated and the regulatory pattern was established. α‐Aminodipate reductase (Mr 160,000), saccharopine reductase (Mr 90,000) and saccharopine dehydrogenase (Mr 45,000) were separated from each other. Homocitrate synthase was sensitive to the separation methods used. The formation of saccharopine reductase was constitutive, whereas the synthesis of homocitrate synthase, α‐aminoadipate reductase and saccharopine dehydrogenase were regulated by the general control of amino acid biosynthesis. l‐Lysine (Ki = 5.0 mm), l‐thialysine (Ki = 15 mm) and dl‐α‐aminoadipate (Ki = 5.1 mm) inhibited homocitrate synthase, the first enzyme of the pathway. The inhibition was competitive with respect to 2‐oxoglutarate. The Km‐values of the enzyme were estimated to be 0.033 mm for acetyl‐CoA and 0.025 mm for 2‐oxoglutarate. The Michaelis constants of the α‐aminoadipate reductase were calculated to be 0.20 mm for α‐aminoadipate, 0.50 mm for ATP, 0.10 mm for NADPH and 3.8 mm for MgCl2. The Km‐values of the saccharopine reductase were 0.55 mm for saccharopine and 0.13 mm for NADP+, respectively. The values of the saccharopine dehydrogenase were estimated to be 1.6 mm for l‐lysine, 0.66 mm for 2‐oxoglutarate and 0.23 mm for NADH. Furthermore, a number of amino acids were found to be effectors of the enzyme reactions.