On the biocatalytic cleavage of silicon-oxygen bonds: A substrate structural approach to investigating the cleavage of protecting group silyl ethers by serine-triad hydrolases

Andy Maraite, Marion B. Ansorge-Schumacher, Benjamin Ganchegui, Walter Leitner, Gideon Grogan

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The biotransformation of compounds containing silicon has recently been a subject of much interest. In this study, a variety of commercially available serine hydrolases were tested for their ability to catalyse the hydrolysis of the silicon-ether bond in a variety of silyl ethers. The hydrolysis of trimethylethoxysilane in buffer was not found to be accelerated by the presence of trypsin, chymotrypsin, or a variety of other lipase and protease enzymes. Cleavage of a range of alternative silyl ether substrates, including a trimethylsilyl (TMS) ether, by these hydrolases was also not observed, but, interestingly, only two of the enzymes tested were able to cleave a t-butyl alpha,alpha,alpha-carboxylate that was approximately isosteric with the TMS-protected substrate. This suggests that the cleavage of Si-O bonds by serine hydrolases, such as the cathepsin homolog silicatein-alpha, may be in part limited by steric effects, as the reactive centre in the substrate is always, by analogy to C-centred substrates, tertiary, and thus inherently sterically demanding regardless of the putative catalytic competence of the enzymes. (C) 2008 Elsevier B.V. All Fights reserved.

Original languageEnglish
Pages (from-to)24-28
Number of pages5
JournalJournal of Molecular Catalysis B : Enzymatic
Issue number1
Publication statusPublished - Jan 2009


  • Enzymes
  • Protecting groups
  • Silylethers
  • Tertiary acids
  • Serine hydrolases

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