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The pK(sub a) of the general acid/base carboxyl group of a glycosidase cycles during catalysis: a 13C-NMR study of Bacillus circulans xylanase
- Source :
- Biochemistry. August 6, 1996, Vol. 35 Issue 31, p9958, 9 p.
- Publication Year :
- 1996
-
Abstract
- Selective isotopic labelling and 13C-NMR studies on the pK(sub a) values of the catalytic glutamic acid residues in wild type/mutant Bacillus circulans (BCX) and subtilis xylanases reveal a two-step hydrolysis mechanism involving a covalent glycosyl-enzyme intermediate. The double-displacement reaction of BCX may be broken into glycosylation and deglycosylation steps. The glycosylation step produces the glycosyl-enzyme intermediate and deglycosylation regenerates the native enzyme. These protonation and deprotonation steps are governed by glutamic ionization states.
Details
- ISSN :
- 00062960
- Volume :
- 35
- Issue :
- 31
- Database :
- Gale General OneFile
- Journal :
- Biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- edsgcl.18834462