This standard applies to the determination of catalase activity in commercial grains. GB/T 5522-1985 Grain and oilseed inspection - Determination of catalase activity GB/T5522-1985 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Inspection of grain and oilseedsMethods for determination of hydrogen peroxidase activity
Inspection of grain and oilseedsMethods for determination of hydrogen peroxidase activityThis standard applies to the determination of catalase activity in commercial grains. 1 Apparatus and equipment
1.1 Constant temperature water bath,
1.2 Electric furnace,
1.3 Centrifuge or suction filter;
1.4 Conical flask: 100ml,
1.5 Measuring cylinder: 10, 15ml,
1.6 Pipette 5, 10, 20ml,
1.7 Mortar,
1.8 Burette, narrow-necked bottle, funnel, etc.
2 Reagents
2.13% hydrogen peroxide solution, take 30% hydrogen peroxide solution 3ml and dilute it to 30ml with water, 2.210% sulfuric acid solution,
2.30.1N potassium permanganate solution,
2.4pH7.7 Sorenson phosphate buffer, Liquid A, weigh 11.876g disodium hydrogen phosphate and dissolve it in 11 water. Liquid B, weigh 9.078g potassium dihydrogen phosphate and dissolve it in 11 water. When using, mix liquid A and liquid B in a ratio of 9:1. 2.5 Quartz sand or fine sand made by grinding clean glass pieces. 3 Operation method
UDC (633.1+633.85)wwW.bzxz.Net
.001.4
GB5522—85
3.1 Extraction of catalase: Weigh the sample (can be converted into 1g of anhydrous sample), put it into a mortar, add a small amount of fine sand, measure 50ml of buffer solution, first pour out 5-10ml and grind the sample in the mortar, then pour it into a conical flask through a funnel, wash the mortar and funnel with the remaining buffer solution, then pour the washing liquid into the conical flask, shake it and let it stand for 2-3h, and obtain a transparent extract by suction filtration or centrifugal precipitation. 3.2 Determination of enzyme activity: Shake the extract, draw 20ml into a conical flask, add 20ml water and 3ml 3% hydrogen peroxide solution, place at room temperature for 15-30min, add 5ml 10% sulfuric acid solution, shake well, titrate the remaining hydrogen peroxide with 0.1N potassium permanganate solution, and record the milliliters of potassium permanganate solution used (V,). 3.3 Control test: draw 20ml extract into a conical flask, heat it in a boiling water bath for 5min, or destroy catalase by direct boiling. Add 20ml water and 3ml 3% hydrogen peroxide solution to a conical flask, place it at room temperature for 15-30min, then add 5ml 10% sulfuric acid, shake well, titrate with 0.1N potassium permanganate solution, and record the milliliters used (V,). Issued by the National Bureau of Standards on November 2, 1985
Implemented on July 1, 1986
4 Calculation of results
The activity of catalase is calculated according to the following formula: GB 5522-85
The activity of catalase (mgH,O./1g sample) = (V2-V,)×N×17×20
Wherein: V1-volume of 0.1N potassium permanganate solution used in enzyme activity determination, ml, V2-volume of 0.1N potassium permanganate solution used in control test, ml, N-——equivalent concentration of potassium permanganate solution; 17——milligram equivalent of H02.
The allowable difference between the two test results shall not exceed 10% of the average value, and the average value shall be taken as the test result. The test result shall be rounded to the first decimal place. Additional remarks:
This standard is proposed by the Ministry of Commerce of the People's Republic of China. This standard is drafted by the Grain Storage and Transportation Bureau of the Ministry of Commerce. The main drafters of this standard are Gao Xiuwu, Yang Haoran, Wu Yanxia and Lv Guifen.
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