Glucosidase-catalysed hydrolysis

Duroux, L. et al.. Insight into napthoquinone metabolism 3-glucosidase-catalysed hydrolysis of hydrojuglone 3-pyranoside, Biochem. J., 333, 275, 1998. 

Raspberry ketone [4-(4 -hydroxyphenyl)-butan-2-one], the impact compound found in raspberries, can be obtained by enzymatic reactions The first step is the /i-glucosidase-catalysed hydrolysis of the naturally occurring betu-loside to betuligenol. The latter can be transformed into raspberry ketone by microbial alcohol dehydrogenase (Scheme 22.2) [56]. 

Irradiation of the pyridyl thioglycoside (73) caused a complex isomerization to give the jS-iV-bonded compound (74) as well as the a- and j8-C-nucleosides bonded through C-3 and C-5. All were isolated in low yield only. The 1,2,4-thiadiazole thioglucoside (75) has been reported,and the acid- and almond /3-glucosidase-catalysed hydrolysis of the purine compound (76) and its 2 -deoxy analogue have been investigated. As expected, the latter is the more sensitive in acid solution, but the former is the better enzyme substrate. ... 

More specific hydrolysis may be achieved by the use of enzymes. Thus, the enzyme a-amylase in saliva and in the gut is able to catalyse hydrolysis of al 4 bonds throughout the starch molecule to give mainly maltose, with some glucose and maltotriose, the trisaccharide of glucose. Amylose is hydrolysed completely by this enzyme, but the al 6 bonds of amylopectin are not affected. Another digestive enzyme, a-l,6-glucosidase, is required for this reaction. Finally, pancreatic maltase completes the hydrolysis by hydrolysing maltose and maltotriose. 

The branched-chain compound 27 has been synthesized from 28 (available from D-mannose) by reductive amination then acid-catalysed hydrolysis. Compounds 27 thus prepared together with related compounds were tested for their inhibition against human blood purine nucleoside phosphorylase and a- and P-glucosidases. ... 

An Aspergillus niger a-glucosidase catalyses the slow hydrolsys of -D-glucopyranosyl fluoride which competitively inhibits the hydrolysis of p-nitrophenyl a-0-glucopyranoside and thus binds at the same site as do substrates of the en me. ... 

B. W. Sigurdskjold, B. Duus, and K. Bock, Hydrolysis of substrate analogues catalysed by P-D-glucosidase from Aspergillus niger. Part II Deoxy and deoxyhalo derivatives of cellobiose, Acta Chem. Scand., 45 (1991) 1032-1041. 

Myrosinases are the only known S-glucosidases. Whereas some myrosinases exhibit a pronounced substrate specificity towards glucosinolates (e.g. MacLeod and Rossiter, 1986 Bernardi et al, 2003), most of these hydrolytic enzymes, myrosinases, accept multiple glucosinolate substrates e.g., Chen and Halkier, (1999). However, the hydrolysis of other S- or 0-glucosides is only poorly catalysed by these enzymes (Lein, 1972 Durham and Poulton, 1990 Bernardi et al, 2003). 

Reagents i, catalytic reduction ii, controlled hydrolysis iii, NaBH iv, mild basic hydrolysis v, controlled acid-catalysed decarboxylation vi, base vii, / -d-glucosidase viii, LiAlH4 ix, NaBH4-AcOH... 

Antibodies have been raised against a purified jS-o-acetamidodeoxyhexosidase obtained from D. discoideumP Ouchterlony tests produced single precipitin bands with both )8-D-acetamidodeoxy-glucosidase and -galactosidase activities, which were co-precipitated in identical proportions in quantitative immuno-precipitation reactions. It was concluded that one species of enzyme catalyses the hydrolysis of both 2-acetamido-2-deoxy-jS-D-gluco- and -galacto-pyranosides. 

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