Page 50 - Pharmd general phytochemistry I-Final2024_LEUCTERS

the coexisting enzymes. However, upon powdering, grinding, …the cell
walls are destroyed and the glycosides are acted upon by the enzymes.
The enzymatic hydrolysis is selective and specific
Distinction of the glycosidic linkage
(1)- Using universal enzymes:
-Emulsin: (a mixture of β- enzymes) can hydrolyze most β-glycosides.
(Universal β-glycosidase)
- Invertase: (α- enzymes) can hydrolyze most α -glycosides.
(Universal α-glycosidase)

(2)- Measuring the optical rotation:
• Pure α glucose has specific rotation = + 112.2 degrees
• Pure β- glucose has specific rotation + 19 degrees)

The α and β anomers of glucose are present in equlibrium mixture
with a specific rotation of 52.6 degrees.

 α-glucose has a higher specific rotation than β-glucose.
1- Hydrolyze the glycoside by acid and immediately measure the optical
rotation of the solution.
2- Repeat the measuring of the optical rotation at time intervals.
3- Record the pattern of change in the optical rotation.
# If the solution shows gradual decrease in the optical rotation till
equilibrium α-glycoside

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