Tweezing-adsorptive bubble separation. Analytical method for the selective and high enrichment of metalloenzymes

Anal Chem. 2005 Oct 1;77(19):6113-7. doi: 10.1021/ac050977s.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorption
  • Binding Sites
  • Chelating Agents / chemistry
  • Chelating Agents / metabolism
  • Horseradish Peroxidase / chemistry
  • Horseradish Peroxidase / isolation & purification*
  • Horseradish Peroxidase / metabolism
  • Laccase / chemistry
  • Laccase / isolation & purification*
  • Laccase / metabolism
  • Metalloproteins / isolation & purification*
  • Metalloproteins / metabolism
  • Models, Molecular
  • Protein Structure, Tertiary

Substances

  • Chelating Agents
  • Metalloproteins
  • Laccase
  • Horseradish Peroxidase