The Action of Enzymes on Melezitose

The augmented formula of p. 30 for melezitose, S- a-D-glucopprano-8pl]-D-/rudo/Mrano8e n-glucopyranose, lacks only the two pertinent a,p allocations. In the case of the D-glucopyranose unit there is evidence from enzyme studies, which seems conclusive, that it is of the a-D-type, as in sucrose. First, there is the evidence of a negative kind that the 

The rather complicated enzymic hydrolyses of three of the tri-saccharides receive a clear interpretation through the relationships that are shown in Table IV. 

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

The non-reducing disaccharide unit of raffinose and gentianose is certainly sucrose, as previously mentioned in the case of melezitose all that can be said with assurance at the present time is that this sugar is S-[a T)-glucopyranosylJ-( )-D-fructofuranosyl-a-D-fflucopyranoside. It would indeed be surprising, from biological views, if the now unknown disaccharide component should eventually prove to be other than sucrose. 

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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. 

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