HETEROTROPHIC CARBON-DIOXIDE FIXATION BY EUGLENA FUNCTION OF PHOSPHOENOLPYRUVATE CARBOXYLASE
HETEROTROPHIC CARBON-DIOXIDE FIXATION BY EUGLENA FUNCTION OF PHOSPHOENOLPYRUVATE CARBOXYLASE
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DOI：
10.1016/0304-4165(81)90251-8
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发表时间：
1981-01-01
期刊：
影响因子：
--
通讯作者：
PEAK, MJ
中科院分区：
文献类型：
--
作者：
PEAK, JG;PEAK, MJ
本文对大肠杆菌羧化酶活性进行了研究。gracilis进行。苹果酸酶（EC 1.1.1.40）、磷酸烯醇丙酮酸[PEP]羧化酶（EC 4.1.1.31）和乙酰辅酶A羧化酶（EC 6.4.1.2）活性存在于所有测试的细胞中。刺激异养CO2固定在体内，暴露于NH 4+的NH 4+剥夺一段时间后的细胞，引起的苹果酸酶和PEP羧化酶的比活性的增加，在粗提取物中测量，但不是乙酰辅酶A羧化酶的活性。PEP羧化酶的两种同工酶从彼此纯化，从NH 4+刺激和非刺激的细胞。从2种类型的细胞的同工酶的洗脱曲线之间没有显着差异，也没有从自养和异养生长的细胞的同工酶的洗脱曲线之间。苹果酸，柠檬酸，琥珀酸和3-磷酸甘油酸的2种同工酶的调节动力学。对NH 4+调节裸藻异养CO2固定的机理进行了讨论。
A survey into the activities of carboxylating enzymes from E. gracilis was conducted. Malate enzyme (EC 1.1.1.40), phosphoenolpyruvate [PEP] carboxylase (EC 4.1.1.31) and acetyl-CoA carboxylase (EC 6.4.1.2) activities were present in all cells tested. Stimulation of heterotrophic CO2 fixation in vivo, by exposure of the cells to NH4+ after a period of NH4+ deprivation, caused an increase in specific activity of malate enzyme and PEP carboxylase measured in crude extracts but not the activity of acetyl-CoA carboxylase. Two isoenzymes of PEP carboxylase were purified from each other, from both NH4+-stimulated and non-stimulated cells. No significant differences were found between elution profiles of isoenzymes from the 2 types of cells, nor between elution profiles of isoenzymes from autotrophically and heterotrophically grown cells. Kinetics of the regulation of the 2 isoenzymes by malate, citrate, succinate and 3-phosphoglycerate are presented. An hypothesis for the mechanism of regulation of heterotrophic CO2 fixation in Euglena by NH4+ is discussed.