2,5-Dinitrosalicylic acid

The PG activity was measured [10] by detecting the increase of reducing groups during the depolymerisation of 1 % (w/v) polygalacturonic acid buffered solutions, by a colorimetric method based on the 3,5-dinitrosalicylic acid. 

Pb salt of dinitrosalicylic acid is used, with MF or other additives, as a priming chge)... 

Wang, G., Michailides, T.J., and Bostock, R.M. 1997. Improved detection of polygalacturonase activity due to Mucorpiriformis with a modified dinitrosalicylic acid reagent. Phytopathology 87 161-163. 

Dj potassium 3,5-Dinitrosalicylate (3,5-Dinitro-2-Hydroxybenzoic Acid, Dipotassium Salt), K2C7H207N2.H20 mw 322.33 N 8.69% OB to C02 --39.71% dark red ndles mp 280° (ignites). Sol in hot w and hot aq ethanol. Prepn is by reacting 2 moles of coned aq KOH with one mole of 3,5-dinitrosalicylic acid Hie Dipotassium salt has an impact sensy of 40cm (complete detonation) and sliding-rod test results of no detonations/all trials at angles of 45° and 75° (Ref 2)... 

Enzyme activity towards carboxylmethyl cellulose (CMC) was measured by combining 50 fiL enzyme with 0.5 mL of 0.5% CMC in pH 4.8 sodium citrate buffer and incubating at 50°C for 10 min. After this, the reaction was stopped by addition of 1.5 mL dinitrosalicylic acid reagent and the resultant color, which was measured at A54onm, related to the reducing sugar concentration. 

Hydroxy-3-butenonitrile, see l-Cyano-2-propen-l-ol, 1463 4-Hydroxy-fraws-cinnamic acid, 3130 Hydroxycopper(II) glyoximate, 0795 4-Hydroxy-3,5 -dimethyl-1,2,4-triazole, 1570 4-Hydroxy-3,5-dinitrobenzenearsonic acid, 2213 2-Hydroxy-3,5-dinitrobenzoic acid, see 3,5-Dinitrosalicylic acid, 2661 2-Hydroxy-3,5-dinitropyridine, 1816 N-Hydroxydithiocarbamic acid, 0453 2(2-Hydroxyethoxy)ethyl perchlorate, 1638 (9-(2-Hydroxyethyl)hydroxylamine, 0940... 

Dinitrosalicylic acid (0.5% in 4% sodium hydroxide) Brown spots (sensitivity 1 pg) 3... 

For enzyme uptake studies, 0.1 g of substrate (corn flour or carboxym-ethylcellulose) and 24 mL of buffer were added to a 40-mL jacketed reactor. The temperature was maintained at 52 2°C using a water bath. A 1.5-mL "blank" sample was collected from the reaction mixture and added to 3 mL of the dinitrosalicylic acid (DNS) reagent. Then 500 pL of the soluble enzyme was added to the reactor to initiate the reaction. Samples were collected every 3 min, and the DNS assay (4) was performed for all the samples. One unit of enzyme releases 1 pmol of reducing groups/min, the absorbance of which can be measured at 540 nm. Thus, the amount of activity transferred to the support can be determined from the sugar pro-... 

The culture supernatant was used for determination of glucose concentration by the dinitrosalicylic acid method (11) and pH measurement. Cell growth was monitored by the determination of optical density (OD) at 600 nm in a spectrophotometer (Shimadzu-UV 1601). One OD600 unity was found to be equivalent to 0.46 mg dry cell weight (DCW). Asparaginase II activity was assayed using fresh cells as previously described (3,4). 

The activity of the cellulytic enzymes was measured as filter paper activity units. A1 x 6 cm strip of Whatman No. 1 filter paper was added to a total volume of 1.5 mL of enzyme solution containing 0.05 M citrate buffer, pH 4.8. All enzyme activity measurements were carried out in triplicate. The samples were incubated for 1 h at 50°C. Reducing sugars were determined after stopping the hydrolysis by adding 3 mL of dinitrosalicylic acid solution followed by boiling for 5 min. After cooling, 20.0 mL of distilled water was added and the absorbance was read at 540 nm (21). 

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