Somogyi-Nelson method

Alternate Protocol 1 Determination of Reducing Sugars Using the Somogyi-Nelson Method... 

DETERMINATION OF REDUCING SUGARS USING THE SOMOGYI-NELSON METHOD... 

The reference describes the analysis of reducing sugars using the Somogyi-Nelson method. It contains no experiments, but it is one of the first compilations explaining the method currently in use today. 

The Chi in the hairy roots and parent plant organs was extracted with a mixture of 80% acetone and 20% phosphate buffer (2.5 mol m 3,pH 7.8), and analyzed according to the method described by Porra et al. [17]. The activities of SOD and POD in the hairy roots and parent plant organs were spectrophoto-metrically determined using ferricytochrome C [18] and o-aminophenol [19], respectively. Fructose in the medium was analyzed by the Somogyi-Nelson method [20] or was determined using an HPLC with a refractive index detector. Light intensity was measured with a thermopile on the outer walls of flasks at the level of the medium surface or at the top of the Petri dish, and expressed as the mean of values determined at several positions. 

Obtained from the QCM method in 20 mM acetate buffer, pH 5.2, 150 mM NaCl, 25 °C Obtained from Somogyi-Nelson method in the bulk solution at 20 mM acetate buffer. 

The enzyme reactions were carried out in 0.2 M acetate buffer at pjj 5.2 and 37 0 by adding the enzyme solution to the substrate solution in a test tube with a micropipette. At appropriate intervals 0.2 ml samples of the hydrolysate were taken and the reducing values were measured by the Somogyi-Nelson method (14). 

When p-nitrophenyl a-L-arabinofuranoside is used, the amount of p-nitrophenol released is assayed by measuring the absorption at 400 nm. When phenyl a-L-arabinofuranoside or beet L-arabinan is used, the amount of L-arabinose produced is measured by the Nelson-Somogyi method.3233... 

For enzyme assay, (1— 5)-L-arabinan is the best substrate.4 Reducing groups produced after enzymic action are determined by the Nelson-Somogyi method. One unit of the enzyme is the amount that liberates one //mol of reducing groups from (1— 5)-L-arabinan per minute at 30°. 

Nelson, N. 1944. A photometric adaptation of the Somogyi method for the determination of glucose. J. Biol. Chem. 153 375-380. 

Nelson, N. (1944). A Photometric Adaptation of the Somogyi Method for the Determination of Glucose. J Biol Chem 153 375. 

The assay procedures usually involve the measurement of the increase in reducing end-groups by the Nelson-Somogyi,70,74,76,78 Shaffer-Somogyi,68,69 or the Sumner24 method. 

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