TY - JOUR
T1 - 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
AU - Maraite, Andy
AU - Ansorge-Schumacher, Marion B.
AU - Ganchegui, Benjamin
AU - Leitner, Walter
AU - Grogan, Gideon
PY - 2009/1
Y1 - 2009/1
N2 - 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.
AB - 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.
KW - Enzymes
KW - Protecting groups
KW - Silylethers
KW - Tertiary acids
KW - Serine hydrolases
KW - ALCOHOLS
KW - BIOTECHNOLOGY
KW - LIPASES
UR - http://www.scopus.com/inward/record.url?scp=56049114233&partnerID=8YFLogxK
U2 - 10.1016/j.molcatb.2008.04.006
DO - 10.1016/j.molcatb.2008.04.006
M3 - Article
SN - 1381-1177
VL - 56
SP - 24
EP - 28
JO - Journal of Molecular Catalysis B : Enzymatic
JF - Journal of Molecular Catalysis B : Enzymatic
IS - 1
ER -