Can the Sucrose/D-Fructose/D-Glucose Assay Kit (K-SUFRG) be used to measure Total Sugars (inverted)?

Yes, the Sucrose/D-Fructose/D-Glucose Assay Kit (K-SUFRG) can be used to measure Total Sugars (inverted).

Total Sugars (inverted) relates to the concentration of free reducing sugars (D-fructose and D-glucose) plus those released from sucrose after "inversion".

Inversion of sucrose describes the reaction where sucrose is hydrolysed (split) into free D-fructose and D-glucose.

ASSAY:

To run the assay for Total Sugars (inverted) the user needs to run the "Blank sucrose sample" & "Sucrose sample" reactions as per page 6 in the kit booklet but also include the addition of suspension 4 (PGI) 0.02 mL.

1. Add solution 6* (β-fructosidase) 0.20 mL
2. Add sample solution 0.10 mL
3. Mix**, incubate for 5 min
4. (NOTE: before pipetting solution 6, first warm it to 25-30°C).
5. Add distilled water (at ~ 25°C) 1.90 mL
6. Add solution 1 (buffer)  0.10 mL
7. Add solution 2 (NADP+/ATP) 0.10 mL
8. Mix**, read absorbances of the solutions (A1) after approx. 3 min and start the reactions by addition of:
9. suspension 3 (HK/G6P-DH) 0.02 mL
10. suspension 4 (PGI) 0.02 mL
11. Mix**, read the absorbances of the solutions (A2) at the end of the reaction (approx. 10 min). If the reaction has not stopped after 5 min, continue to read the absorbances at 2 min intervals until the absorbances remain the same over 2 min***.

For the Blank sample do not add sample but add 2.0 mL water instead of 1.9 mL at Step 5.

CALCULATION:

Total Sugars (inverted) g/L = (A2-A1 sample) - (A2-A1 blank) x 0.6978