絲状菌類の蛋白分解酵素に関する研究(第4報) : ゼラチン液化力の一新定量的測定方法に就て

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Several methods have been developed for the determination of the activity of the proteolytic enzymes of molds based on the measurement of its gelatin-liquefying power, but either has bot been sufficiently quantitative or not been simple and rapid enough to yield reliable data.The present paper describes a new method for the quantitative determination of the activity of the proteolytic enzymes of molds.The method is based on the well known principle, that the coagulating property of gelatin, when cooled in ice water, decreases in accordance with the degree digested by the enzyme.The procedures of the determination are as follows : Into each of ten test tubes with the identical diameter of 1.5cm are pipetted 5ml of 2.5% gelatin solution which has been prepared by dissolving 25 gm of gelatin of good quality and 0.1 gm of thymol in distilled water and then diluted to the volume of 1 L at 40℃; the reaction of the solution should be adjusted to pH 8.0 with NaOH before dilution. The following volumes of enzyme are added to each tube successively, followed by the addition of distilled water to make a final volume of 6 ml; 0.1,0.2,0.3 ……0.7,0.8,0.9,and 1.0 ml. The time of each addition is noted. The tubes are shaken well and kept in the thermostat at 40℃. After 15 min of digestion, the tubes are transfered in ice-water and left alone still for 15 min. Observations are then made by inclining the test tubes. If all tubes were digested to liquid, the procedure must be repeated with ten or hundred times dilution of the enzyme. Provided the tube, to whichi 0.6 ml of the enzyme has benn added, is solid and the tube corresponding to 0.7 ml of the enzyme is fluid, repeated procedure must be carried on with the enzyme concentrations of 0.60,0.625,0.650,0.675,and 0.70 ml to determine the point at which the liquefaction of gelation just occurs. The enzymatic power is deduced from the following formula, P_g=1/V×D Where, P_g represents the proteolytic power; V the quantity of enzyme added to the tube at which the liquefaction of gelatin just occurred; and D the dilution of the enzyme.
公益社団法人日本生物工学会の論文
1953-11-15

絲状菌類の蛋白分解酵素に関する研究(第4報) : ゼラチン液化力の一新定量的測定方法に就て

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