pH和缓冲剂对基质结合和cis-aconitate脱碳酶催化物的作用
Mingming Zhao1, Chutao Chen2, Wulf Blankenfeldt1,3
1Department of Structure and Function of Proteins, Helmholtz Centre for Infection Research, Braunschweig, Germany.
酸盐缓冲器可以抑制cis-aconitate脱碳酶 (ACOD1) 的活性. 优化缓冲和pH值揭示了动力学见解,表明多个质子化histidines对于这种itaconic酸合成酶的基质结合至关重要.
科学领域:
- 生物化学 生化学
- 酶学 是一种酶学.
- 免疫学 免疫学 免疫学
背景情况:
- cis-Aconitate脱碳酶 (ACOD1) 在髓状细胞中合成 itaconic 酸.
- 活性部位中的西斯蒂丁残留物对ACOD1的脱碳氧化功能至关重要.
- 标准测试使用HPLC测量伊塔康酸的产量,通常采用酸缓冲剂.
研究的目的:
- 研究缓冲区类型和pH对人类,小鼠和阿斯伯吉勒斯土壤ACOD1.1.的酶动力学的影响.
- 为了确定ACOD1活动测量的最佳测定条件.
- 阐明活跃部位丁质子在基质结合中的作用.
主要方法:
- 酶动力学测试是在5.5-8.25.25的pH范围内进行的.
- 评估了酸盐缓冲区对ACOD1活性的抑制作用.
- 测试被调整为96孔微型位板格式,以实现更高的吞吐量.
主要成果:
- 发现高度的酸盐缓冲剂可以抑制人类,老鼠和阿斯伯吉洛斯地土 ACOD1.1.
- 酶动力学显示,在生理相关的pH值 (7.5-8.25) 时,KM值显著增加.
- 确定了另一种缓冲器,并优化了测试以提高吞吐量.
结论:
- 酸盐缓冲器可以显著抑制 ACOD1 的活性,因此需要仔细选择缓冲器来进行准确的动力学研究.
- 最佳的ACOD1活性和基质结合发生在特定的pH范围内,而更高的pH值会对酶动力学产生负面影响.
- 这些发现表明,多个活性部位的西斯蒂丁残留物的质子化状态对于ACOD1.1的有效基质结合和催化是至关重要的.
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