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Deoxyribonuclease II - Assay
Source:
Porcine Spleen
CAS:
9025-64-3
EC:
3.1.22.1
Deoxyribonuclease II Assay
Method
That developed by Kunitz (1950) based upon the increase in absorbance at 260 nm during the hydrolysis of DNA. The method has been adapted from that used for DNase I by reducing the pH to 4.6 and lowering the magnesium concentration to 0.001 M. One unit causes an increase in absorbance at 260 nm of 0.001 per minute per ml at 25°C and pH 4.6 under specified conditions. Bernardi (1971) discusses the relationship of absorbance units so defined to terminal phosphate formation, i.e., substrate bonds hydrolyzed.
Reagents
- 1.0 M Acetic acid, pH 4.6
- 0.02 M Magnesium sulfate
Substrate: Dilute 12.5 ml of 0.02 M magnesium sulfate to a volume of 200 ml with reagent grade water. Add 10 mg Worthington calf thymus DNA (Code: DNA). Let stand overnight at room temperature. Add 25 ml of 1.0 M acetic acid, pH 4.6 and adjust the pH to 4.6. Dilute to a final volume of 250 ml with reagent grade water. Store at 2 - 8°C.
Enzyme
Dissolve enzyme at one mg/ml in reagent grade water. Dilute further in water immediately prior to use to a concentration of 50 - 150 units/ml.
Procedure
Adjust the spectrophotometer to 260 nm and 25°C.
Pipette 2.5 ml of substrate into cuvette and incubate in the spectrophotometer for 3 - 4 minutes to establish blank rate, if any, and to reach temperature equilibrium. Add 0.5 ml diluted enzyme. Record increase in A260 from linear portion of curve. Note: the change in A260 for this assay is not generally linear from the initial time and is linear for only short periods. The change in A260 should be determined from the portion which is most linear.
Calculation
Deoxyribonuclease II Products
Description
Activity
Code
Cat. #
Size
Price
Description
Deoxyribonuclease II
Source:
Porcine Spleen
A dialyzed, lyophilized powder.
Store at 2-8°C.
Code
HDA
Product details
LS002425
80 ku
$90.00
LS002427
Bulk
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Description
Deoxyribonuclease II, Purified
Source:
Porcine Spleen
Chromatographically purified in a modification of the procedure of Bernardi, et al., BBA, 129, 1 (1966). A dialyzed, lyophilized powder.
Store at -20°C.
Ice Pack required
Code
HDAC
Product details
LS005410
20 ku
$260.00
LS005411
Bulk
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Description
Deoxyribonuclease II, Purified, Solution
Source:
Porcine Spleen
Chromatographically prepared. A solution in 50% glycerol.
Store at -20°C.
Ice Pack required
Code
HDACS
Product details
LS005416
2 ku
$63.00
LS005418
5 ku
$145.00
LS005420
Bulk
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