Tweezing-Adsorptive Bubble Separation. Analytical Method for the Selective and High Enrichment of Metalloenzymes
作者:Birte M. Gerken、Carsten Wattenbach、Diana Linke、Holger Zorn、Ralf G. Berger、Harun Parlar
DOI:10.1021/ac050977s
日期:2005.10.1
A novelly developed tweezing-adsorptive bubble separation (ABS) method for the enrichment of metalloenzymes (laccase C and horseradish peroxidase) is introduced. The method is based on the chelation of the enzymes' active center and can also be applied for analysis. N-(2-Acetamido)iminodiacetic acid served as a chelator and was synthesized with an octyl unit to become ADA-C8. Laccase was enriched 13.3-fold (66.31% recovery) and HPOX 17.8-fold (85.34%) without a significant loss of enzymatic activity. To prove that the entire enzyme is tweezed at the active center, ABS trials were done using ADA-C8 already complexed with Cu2+ and Fe3+. As only marginal enrichment occurred (ER laccase, 0.17; ER HPOX, 0.44), no chelating effect was concluded. It was determined how the chelation toward the active center was directed by applying other chelators such as EDTA, NTA, N,N-dimethylaminoglycine, oxalic acid, malonic acid, adipinic acid, and tripropylamine, which are similar in structure to ADA-C8. The results concluded that the chelation is 3-fold coordinated on the type 1 copper center of laccase, whereas that of HPOX only 1-fold at Fe3+ and additionally at the cationic amino acid arginine, which is also located at the active center. Tweezing-ABS has been proven to selectively and effectively enrich metalloenzymes.
介绍了一种用于富集金属酶(漆酶 C 和辣根过氧化物酶)的新开发的镊子吸附气泡分离(ABS)方法。该方法基于酶活性中心的螯合作用,也可用于分析。N-(2-Acetamido)iminodiacetic acid 可作为螯合剂,并与辛基单元合成为 ADA-C8。漆酶富集了 13.3 倍(回收率为 66.31%),HPOX 富集了 17.8 倍(回收率为 85.34%),而酶活性没有明显下降。为了证明整个酶的活性中心被镊子夹住,使用已经与 Cu2+ 和 Fe3+ 复合的 ADA-C8 进行了 ABS 试验。由于只发生了轻微的富集(ER 漆酶,0.17;ER HPOX,0.44),因此没有得出螯合作用的结论。通过使用其他螯合剂,如 EDTA、NTA、N,N-二甲基氨基甘氨酸、草酸、丙二酸、己二酸和三丙胺(这些螯合剂的结构与 ADA-C8 相似),确定了如何将螯合作用引向活性中心。结果表明,螯合作用在漆酶的 1 型铜中心上有 3 倍配位,而 HPOX 的螯合作用仅在 Fe3+ 上有 1 倍配位,此外,阳离子氨基酸精氨酸也位于活性中心。事实证明,Tweezing-ABS 能选择性地有效富集金属酶。