Yeast a-glucosidase

Because sucrose is hydrolyzed by enzymes that specifically assist hydrolysis of both a glycosides (such as yeast a-glucosidase) and /3-fructosides (such as invertase), it is inferred that the glucose residue is present as an a glucoside and the fructose residue as a /3 fructoside. If so, the remaining uncertainty in the structure of sucrose is the size of the rings in the glucose and fructose residues. 

An analogous mechanism that relies on proton transfer and nucleophilic attack is apparently operative with aziridine derivatives of conduritol and deoxynojirimycin. Preliminary studies show both compounds are effective inhibitors the conduritol B aziridine (X) irreversibly inactivates Alcaligenesfaecalis )3-glucosidase and yeast a-glucosidase (2i8),and the ga/ac/odeoxynojirimycin aziridine (XI)... 

Dideoxy-1,4-imino-D-arabiiutol 2R, >RAR)-2-hydroxymethyl pyrrolidine-3,4-diol, DABl, 1] has been found in ho h Arachniodes standishii andAngylocalyx boutiqueanus and it is a potent inhibitor of yeast a-glucosidase (50% inhibition at 1.8 x 10 ... 

Bacillus cereus, against, 64 bacterial infections, 240 bacterial lipopolysaccharides, 1 Baker s yeast a-glucosidase inhibitor, 11 biochemistry and pathology in big, 320 biological, 1,75, 105, 193, 209, 212,... 

In the yeast a-glucosidase-catalyzed hydrolysis of 4-nitrophenyl-a-D-glucopyr-anoside," the primary leaving group KIE was unity, 1.001, and the a-secondary... 

KIEs on Emax were investigated for the yeast a-glucosidase-catalyzed hydrolysis of... 

The )8-secondary KIEs for yeast a-glucosidase-catalyzed hydrolysis of 10 and 11 are suggestive of substantial overlap of a C-H(D) bond with the p-orbital at the transition state, consistent with the glycosyl ring approaching a boat conformation. Hosie and Sinnott had reported a similar value for the )8-secondary HKIE on 10 as well as a large value for 12." ... 

The primary KIEs for the spontaneous hydrolysis of 12 (1.018, corrected to 25°C) and the yeast a-glucosidase-catalyzed hydrolysis of 10 (1.019) suggested transition states with partial C-N bond cleavage. Similar results were found in a study by Scheming and Schramm on pertussis toxin-catalyzed hydrolysis of NAD. ° Based on the family of KIEs (primary KIE value of 1.021), semi-empirical calculations and BOVA, these authors concluded that the reaction transition state had partial C-N bond breakage with a weak nucleophilic component from the incoming water molecule. 

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