Emulsin, almond

Emulsin (0-glycoaidase) almond nuts P-glucosides glucose and a non-carbohydrate 4I-4-5... 

Emulsin, an enzyme readily obtained from almonds, has the property of hydrolysing 3-glycosides. 

As early as 1908, Rosenthaler found in the ferment mixture of emulsin a u-oxynitrilase , which directed the addition of hydrocyanic acid (hydrogen cyanide) to benzaldehyde asymmetrically to give x-hydroxybenzeneacetonitrilc (mandelonitrile)9. This result was confirmed1 °, however, it was not until 1963 that Pfeil ct al. first isolated and characterized the enzyme (R)-oxyni-trilase [EC 4.1.2.101 from bitter almonds (Prunus amygdalus)1 12. The yellow-colored enzyme contains a flavin-adenine dinucleotide (FAD)11 and loses its activity by splitting off this prosthet-... 

His work on enzymes was continued during the Bonn period. Studies on acid phosphatases were carried out that made a major contribution to our knowledge of these enzymes. " The isolation of a crystalline /3-glucosidase from the emulsin of sweet almonds may be regarded as the crowning achievement of his work on glycosidases. ... 

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

C3 and C4 of the glucon is an absolute one. Phenyl a-D-glucoside, phenyl /J-D-mannoside (II), methyl /S-D-guloside (III), involving reversal of the addenda at Cl, at C2, at C3 and C4, respectively, are not appreciably hydrolyzed by almond emulsin.29 Phenyl /3-D-glucoside (I) and phenyl... 

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... 

Catalytic activities in plant extracts were also recognized early in the nineteenth century. Robiquet and Boutron (1830), for example, noted the hydrolysis of amygdalin, a glycoside in the seeds of bitter almonds Robiquet, and Liebig and Wohler then identified the enzyme responsible—emulsin. 

It has also been observed that syringyl-type precursors arc transformed in part into guaiacyl-type lignin 78, 90, 91), i.e. a demethoxyla-tion, not merely a dcmcthylation has taken place. It has also been found that sweet almond emulsin hydrolyses syringin only extremely slowly 143) and that pure peroxidase does not oxidize sinapyl alcohol well 71). The metabolism of the sinapyl component of lignin is perhaps not quite as simple as the analogy between its />-coumaryl and conifcryl components suggests. 

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. 

Emulsin bitter almonds amygdalin hydrolysis Robiquet and Boutron, 1830 ... 

Early work on a-D-mannosidase of plant origin, notably in almond emulsin, has been described.1 There has been a revival of interest in the enzyme from all sources, and an extensive survey of plant... 

Results are expressed as fig of p-nitrophenol liberated per g of seed from 6 mM p-nitrophenyl a-D-mannoside in 1 hr at 37° and pH 5. Coarsely ground beans. Defatted sweet-almond meal. A commercial /3-D-glucosidase preparation purified from emulsin. a-D-Mannosidase activity is given per g of purified material. 

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. 

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