Gerhardt W, Waldenström J, Gruber W
Scand J Clin Lab Invest. 1979 Dec;39(8):737-42. doi: 10.1080/00365517909108165.
The inclusion of EDTA in the creatine kinase reagent recommended by the Scandinavian Committee on Enzymes was shown to increase reagent stability from less than 24 h to 5 days. Part of this effect can be explained by the fact that EDTA delays the formation of inhibitory products formed when N-acetyl cysteine is oxidized. The addition of EDTA to the reagent also results in increased measured CK activity. This effect is more pronounced for CK-BB than for CK-MM. Calcium and ferric ions are shown to inhibit the enzyme and the chelation of these ions can partly explain the observed increase of CK acitivity.
斯堪的纳维亚酶委员会推荐的肌酸激酶试剂中加入乙二胺四乙酸（EDTA）后，试剂稳定性从不足24小时提高到了5天。这种效果部分可以通过以下事实来解释：当N-乙酰半胱氨酸被氧化时，EDTA会延迟抑制性产物的形成。向试剂中添加EDTA还会导致测得的肌酸激酶活性增加。这种效果对肌酸激酶同工酶BB（CK-BB）比对肌酸激酶同工酶MM（CK-MM）更明显。已表明钙和铁离子会抑制该酶，而这些离子的螯合可以部分解释观察到的肌酸激酶活性增加的现象。
