Glucosidase-transferase

Figure 5. The hydrolysis of glycogen phosphorylase limit dextrin by the purified glucosidase-transferase as a function of pH in various buffers. Adapted from...

Figure 11. Double reciprocal plot of the action of the glucosidase-transferase on glycogen phosphorylase limit dextrin in the presence ofTris(ll).

Observed optical rotation during glucosidase-transferase hydrolysis of phosphorylase limit dextrin (15)... 

This procedure is not subject to any of the criticisms resulting from incorrect assumptions regarding the mechanism of debranching or the structure of the phosphorylase limit-dextrin discussed previously, and it has been used routinely with successful results. A deterrent to the use of the procedure is that it requires two purified enzymes, both of which are rather difiBcult to obtain (particularly, free from branching enzyme, which would interfere with the results). Carter and Lee used the same method with yeast glucosidase-transferase instead of muscle glucosidase-transferase. 

The amount (unity) subtracted arises because the free n-glucose liberated by the debranching enzyme is also measured by the redudng-value assay for maltose. This procedure depends on the availability of purified glucosidase-transferase, and this is the main drawback to its application. However, the method has given values in good agreement with those afforded by other methods. ... 

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