Search results for "Glycoside Hydrolases"
showing 3 items of 33 documents
Biochemical and structural features of a novel cyclodextrinase from cow rumen metagenome.
2007
A novel enzyme, RA.04, belonging to the alpha-amylase family was obtained after expression of metagenomic DNA from rumen fluid (Ferrer et al.: Environ. Microbiol. 2005, 7, 1996-2010). The purified RA.04 has a tetrameric structure (280 kDa) and exhibited maximum activity (5000 U/mg protein) at 70 degrees C and was active within an unusually broad pH range from 5.5 to 9.0. It maintained 80% activity at pH 5.0 and 9.5 and 75 degrees C. The enzyme hydrolyzed alpha-D-(1,4) bonds 13-fold faster than alpha-D-(1,6) bonds to yield maltose and glucose as the main products, and it exhibited transglycosylation activity. Its preferred substrates, in the descending order, were maltooligosaccharides (C3-C…
Stereoselective Synthesis of the Glycosidase Inhibitor Australine through a One-Pot, Double-Cyclization Strategy
2006
[reaction: see text] A stereocontrolled, convergent synthesis of the alkaloid australine, a glycosidase inhibitor of the pyrrolizidine class, is described. The chiral starting materials were ketone 3, derived from L-erythrulose, and alpha-alkoxy aldehyde 4, prepared from L-malic acid. A key step of the synthesis was the highly stereoselective aldol reaction between 4 and a Z boron enolate derived from 3. Another key step was the one-pot construction of the bicyclic pyrrolizidine system by means of a three-step sequence of SN2 displacements induced by benzylamine on a trimesylate precursor.
O-linked mannose composition of secreted invertase of Saccharomyces cerevisiae
1989
The secreted invertase (EC 3.2.1.26) of Saccharomyces cerevisiae is a glycoenzyme that contains N- and O-linked mannoses in 40/1 proportion. The small amount of mannose chains O-linked to invertase is distributed as follows: mannose (20%), mannobiose (50%), mannotriose (6%), mannotetraose (7%) and mannopentaose (17%).