Hydrolysis of amylose by β-amylase and Z-enzyme
1955; Elsevier BV; Volume: 59; Issue: 2 Linguagem: Inglês
10.1016/0003-9861(55)90508-7
ISSN1096-0384
Autores Tópico(s)Biofuel production and bioconversion
Resumo1. The observation of Peat et al. (7) that potato amylose is incompletely hydrolyzed with pure β-amylase unless another factor (Z-enzyme) is added has been confirmed. 2. Treatment with hot alkali of the resistant limit dextrin, obtained after hydrolysis of the amylose with β-amylase, has an effect similar to treatment with Z-enzyme in that it causes the residual dextrin to be further hydrolyzed with β-amylase. 3. The exact degree of β-amylolysis depends on the plant material from which the sample of amylose is derived, on the particular subfraction used, or on the previous treatment of the amylose sample. Like natural amylose, synthetic amylose obtained by the action of potato phosphorylase on α-d-glucose 1-phosphate is not completely hydrolyzed by β-amylase. However, its limit of hydrolysis is considerably greater (89%, increased to 93% by the addition of emulsin). 4. The Z-enzyme activity could be removed from the β-glucosidase and laminarase activities in almonds by purification, indicating that the obstacle to hydrolysis by β-amylase is probably not a β-glucosidic linkage. 5. β-Glucosidase and laminarase are shown to be distinct from each other, as well as from Z-enzyme. 6. The intrinsic viscosity of the limit dextrin is found to be approximately 11% lower than that of the parent amylose. This fact has been discussed with regard to the probable location of the anomalous linkage.
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