Partial purification and properties of nicotinamide adenine dinucleotide synthetase from human erythrocytes: evidence that enzyme activity is a sensitive indicator of lead exposure
Partial purification and properties of nicotinamide adenine dinucleotide synthetase from human erythrocytes: evidence that enzyme activity is a sensitive indicator of lead exposure
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人红细胞烟酰胺腺嘌呤二核苷酸合成酶的部分纯化和特性：酶活性是铅暴露的敏感指标的证据
DOI：
10.1182/blood.v75.7.1576.1576
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发表时间：
1990
期刊：
影响因子：
20.3
通讯作者：
KR Tanaka
中科院分区：
文献类型：
--
作者：
CR Zerez;MD Wong;KR Tanaka
我们研究了人红细胞烟酰胺腺嘌呤二核苷酸合成酶的性质。该酶在粗制溶血液中极不稳定，在4℃下24小时后完全失去活性。然而，在EDTA和KCl2存在下，粗制溶血液在20-25℃保持不变，大大提高了NAD合成酶的稳定性(半衰期=10天)。在此条件下，NAD合成酶经DEAE-纤维素柱层析、硫酸铵分级沉淀、透析等步骤纯化3,100倍，得率29%。烟酸腺嘌呤二核苷酸(NAAD)、三磷酸腺苷、镁离子、谷氨酰胺和K+的表观米氏常数分别为0.108、0.154、1.36、2.17和8.32mmoL/L。最适pH为6.8~7.4，相对分子质量为483+/-5kD。Pb~(2+)和Zn~(2+)对该酶有明显的抑制作用，抑制50%所需浓度分别为1.3和2.0mumol/L。完整的红细胞与铅孵育，然后严格清洗以去除铅，几乎消除了所有NAD合成酶的活性。在此条件下，对铅不敏感的葡萄糖-6-磷酸脱氢酶活性不受影响，而对铅敏感的嘧啶5‘-核苷酸酶活性下降30%-50%。更重要的是，铅负荷过重(34至72微克Pb2+/dL血)的患者都显著降低了NAD合成酶活性。这些数据与其他结果一起表明，红细胞NAD合成酶活性是人类铅暴露的敏感指标。
We have examined properties of nicotinamide adenine dinucleotide (NAD) synthetase from human erythrocytes. The enzyme was found to be cold labile and extremely unstable in crude hemolysate, with complete loss of activity occurring after 24 hours at 4 degrees C. However, maintenance of crude hemolysate at 20 to 25 degrees C in the presence of EDTA and KCl increased NAD synthetase stability substantially (half- life = 10 days). Using these conditions, NAD synthetase was purified 3,100-fold with a 29% yield using DEAE-cellulose column chromatography, ammonium sulfate fractionation, and dialysis. The apparent Michaelis- Menten constants for nicotinic acid adenine dinucleotide (NAAD), adenosine triphosphate, Mg2+, glutamine, and K+ were 0.108, 0.154, 1.36, 2.17, and 8.32 mmol/L, respectively. The pH optimum ranged between 6.8 and 7.4, and the molecular weight was estimated to be 483 +/- 5 Kd. The enzyme was markedly inhibited by Pb2+ and Zn2+, with concentrations necessary for 50% inhibition of activity of 1.3 and 2.0 mumol/L, respectively. The incubation of intact red blood cells with lead followed by rigorous washing to remove lead abolished nearly all NAD synthetase activity. In contrast, glucose-6-phosphate dehydrogenase activity, which is not sensitive to lead, was unaffected, whereas pyrimidine 5′-nucleotidase activity, which is sensitive to lead, was decreased 30% to 50% under these conditions. More importantly, patients with lead overburden (34 to 72 micrograms Pb2+/dL blood) all had markedly decreased NAD synthetase activity. These data together with other results suggest that erythrocyte NAD synthetase activity is a sensitive indicator of lead exposure in humans.
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通过红细胞嘧啶 5-核苷酸酶的 HPLC 测定预测血铅。
影响因子：
2.5
作者：
Cook,LR;Angle,CR;Kubitschek,CE;Stohs,SJ
通讯作者：
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丙酮酸激酶缺陷的人红细胞中烟酰胺腺嘌呤二核苷酸合成受损：总 NAD 含量降低的机制和溶血的可能继发原因。
影响因子：
20.3
作者：
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通讯作者：
Tanaka,KR
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影响因子：
2.9
作者：
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通讯作者：
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红细胞磷酸核糖焦磷酸合成酶活性降低和轻度地中海贫血形成受损：腺嘌呤核苷酸含量降低的机制。
DOI：
--
发表时间：
1989
期刊：
The Journal of laboratory and clinical medicine
影响因子：
--
作者：
Zerez,CR;Lachant,NA;Tanaka,KR
通讯作者：
Tanaka,KR
镰状细胞病中红细胞烟酰胺腺嘌呤二核苷酸氧化还原电位降低和吡啶核苷酸含量异常。
影响因子：
20.3
作者：
Zerez,CR;Lachant,NA;Lee,SJ;Tanaka,KR
通讯作者：
Tanaka,KR