Illing N, Hill R T, Woods D R
Department of Microbiology, University of Cape Town, South Africa.
Antonie Van Leeuwenhoek. 1988;54(6):497-507. doi: 10.1007/BF00588386.
Glutamine synthetase (GS) (EC 6.3.1.2) has been purified 67-fold from Nocardia corallina. The apparent Mr of the GS subunit was approximately 56,000. Assuming the enzyme is a typical dodecamer this indicates a particle mass for the undissociated enzyme of 672,000. The GS is regulated by adenylylation and deadenylylation, and subject to feedback inhibition by alanine and glycine. The pH profiles assayed by the gamma-glutamyl transferase method were similar for NH+4-treated and untreated cell extracts and an isoactivity point was not obtained from these curves. GS activity was repressed by (NH4)2SO4 and glutamate. Cells grown in the presence of glutamine, alanine, proline and histidine had enhanced levels of GS activity. The GS of N. corallina cross-reacted with antisera prepared against GS from a Gram-negative Thiobacillus ferrooxidans strain but not with antisera raised against GS from a Gram-positive Clostridium acetobutylicum strain.
谷氨酰胺合成酶（GS）（EC 6.3.1.2）已从珊瑚诺卡氏菌中纯化了67倍。GS亚基的表观分子量约为56,000。假设该酶是典型的十二聚体，这表明未解离的酶的颗粒质量为672,000。GS受腺苷酸化和去腺苷酸化调节，并受到丙氨酸和甘氨酸的反馈抑制。通过γ-谷氨酰转移酶法测定的pH曲线对于NH₄⁺处理和未处理的细胞提取物相似，并且从这些曲线中未获得等活性点。GS活性受到硫酸铵和谷氨酸的抑制。在谷氨酰胺、丙氨酸、脯氨酸和组氨酸存在下生长的细胞具有增强的GS活性水平。珊瑚诺卡氏菌的GS与针对革兰氏阴性氧化亚铁硫杆菌菌株的GS制备的抗血清发生交叉反应，但与针对革兰氏阳性丙酮丁醇梭菌菌株的GS产生的抗血清不发生交叉反应。
