A-D-Glucosidase

The question of a correlation of anomeric specificity of glycosidases with their susceptibility to aldonolactone inhibition was addressed by Reese and coworkers in a comparative study with six fungal a-D-glucosidases and... 

Scheme 4.—Reaction of I-Deoxy-D- /uco-hept-1 -enitol (22) with Retaining and Inverting a-D-Glucosidases.

V al-Met-Ser-Asp-T rp-Ala-Ala-His-His-Ala-Gly-Val-)S-D-Glucosidase A (bitter almonds) lle-Thr-Glx-Glx-Val-Phe-Gly-Asp-Ser-(Ala, Asxj, Glx, Pro)-Lys ff-D-Glucosidase (human placenta, lysosomal) -Val-Ala-Ser-Gln-Lys-Asn-Asp-Leu-Asp-Ala-Val-Ala-a-D-Glucosidase (sucrase, rabbit small intestine) -lle-Asp-Met-Asn-Glu-Pro-Asn-a-D-Glucosidase (isomaltase, rabbit small intestine) -Gly-Gly-Gln-lle-Asp-Met-)ff-D-Galactosidase (Escherichia co//) -Ser-Leu-Gly-Asn-Glu-Ser-Gly-His-Gly-Ala-... 

The Related Enzymic Hydrolyses of Certain Compound Sugars Hydrolyzed by a-D-glucosidase-----------------------,... 

Hig purity /l-D-g uoosidase. The high purity em me grade for kinetic and DSC studies was prepared by a sequential HPSEC and HPIEC procedure, previously reported by Baker et iX. (77), using the Sephacryl S-200 and Mono-Q columns, respectively. This approach yields a -D-glucosidase preparation of approximately 99% purity by SDS-PAGE. 

Although dilute aqueous acid hydrolyzed the methyl and benzyl a-D-fructofuranosides approximately 8 and 16 times as rapidly as sucrose, their method of preparation showed them to be unaffected by any of the enzymes active in a fermenting yeast suspension. Purified yeast invertase, proven free of a-D-glucosidases (maltases), could therefore contain no enzyme capable of hydrolyzing the above two a-D-fructo-furanosides, but did contain constituents that readily cleaved the beta isomers and also sucrose. The latter is accordingly a /S-D-fructofuranos-ide. When the evidence is put in this way, the present uncertainties as to whether purified invertase preparations include one or a number of /3-D-fructofuranosidases, and whether or not sucrose, methyl and... 

The 2,5-iminoglucitol 37 was recently prepared both by a chemoenzymatic synthesis [66] and by chemical means [67],but the synthesis just discussed is an attractive alternative for preparation of this strong a-D-glucosidase inhibitor. 

FlC. 1.—Relative Rates of Activity Against Glycosides at Various pH Values. [A. Hydrolysis of sucrose by /3-D-fructofuranosidase of Saccharomyces cerevisiae O, intact cells and A, toluene-treated cells (results of Wilkes and Palmer40). B. Maltose , fermentation by intact baker s yeast A, hydrolysis by a-D-glucosidase (results of Hestrin41 see also Ref. 42).]... 

Substrate Specificity of Enzymes of Saccharomyces cerevisiae Having a-D-Glucosidase Activity"... 

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