Glucosidases almond emulsin

Glucosidase and 0-galactosidase (sweet almond emulsin)[36] Glutamine synthetase (native octameric brain) 371 Glycogen phosphorylase At3 ]... 

The effect on /3-glucosidase activity of substitution in the glucon has been carefully investigated by the school of Helferich. It has been established that substitution of the hydroxyl groups at C2, C3 and C4 renders the /3-D-glucopyranoside unhydrolyzable (i.e., E.V. less than 10 s) by almond emulsin. This refers to phenyl 3-methyl-/3-D-gluco-pyranoside,29 phenyl 2,4,6-trimethyl-/3-D-glucopyranoside89 and to the... 

D. E. Walker and B. Axelrod, Evidence for a single catalytic site on the P-d-glucosidase-P-D-galactosidase of almond emulsin, Arch. Biochem. Biophys., 187 (1978) 102-107. 

The first evidence for the presence of an a-D-mannosyl link in ovalbumin glycopeptides was provided by the action of almond emulsin,101,102 although the absence of /3-D-mannosidase from the enzyme preparation was not confirmed until later.103 The presence of 2-acetamido-2-deoxy-/M>glucosidase in emulsin left doubt as to the terminal position of all of the D-mannose released. 

It is uncertain whether the -D-galactosidase and the n-glucosidase of sweet almond emulsin are the same or different enzymes. See B. Helferich, Ergtlb. Emymforsch., 7, 83 (1938). 

D-glucosidase of almond emulsin is without action on melezitose or turanose - Next there is the positive evidence that the enzyme a-D-glucosidase which is obtainable from yeast, malt, Aspergillus oryzae and some other organisms, hydrolyzes both turanose and melezitose, the latter to its three components. The action of enzymes thus discloses that both D-glucose units in melezitose are of the a-n-type, and melezitose becomes 3-[ a-o-glucopyrano3ylJ-D-fructofuranose < > a-n-glu-copyranose. 

An enzymic differentiation between the three trehaloses comes from the observation that almond emulsin (/3-D-glucosidase) acts on /3, 8-trehalose much more quickly than on the a,a- or a,/8-isomers, and Peat, Whelan, and Hinson have synthesized /3, 8-trehalose from D-glucose, using ahnond emulsin. 

Foster and Stacey have compiled a comprehensive list of the properties of the known derivatives of glucosamine and galactosamine 316). The phenyl 2-acetylamino-2-deoxyglucosides are hydrolyzed by almond emulsin, but the enzyme (jS-glucosaminidase) differs from the jS-glucosidase which... 

The -configuration for the glucosidic linkage is shown by the hydrolysis of gentiobiose by the jS-D-glucosidase of almond emulsin and by its synthesis imder conditions favorable to the formation of /8-D-glucosides (Koenigs-Knorr synthesis). 

Structure. As shown by G. Tanret, the sugar is hydrolyzed to D-fructose and D-glucose by yeast a-D-glucosidase and, hence, must be an a-D-glucoside. This conclusion receives confirmation from the lack of hydrolysis of the disaccharide by almond emulsin 110). The above evidence and the resistance of the sugar to oxidation by alkaline hypoiodite solutions, coupled with its reduction of alkaline copper salt solutions, show that the unsubstituted hemiacetal group belongs to the fructose component. The mutarotation of turanose resembles that of fructose and probably is caused... 

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