SIMPLE ENZYME REACTIONS 513 (1) HYDROLYSIS OF STARCH BY DIASTASE. Mix 3 g. of starch well with io ml. of water in a test-tube and pour the mixture into 90 ml. of boiling water contained in a 300 ml. conical flask, stirring at the same time. Cool to about 70° and then place in a water-bath maintained at 65-70°, but not higher. Now add 2-3 ml. of the malt extract prepared as above,* mix well and allow the hydrolysis to proceed. Take a series of test-tubes and in each put io ml. of water and 2 drops of a i % iodine solution. At intervals of about 4 minutes (depending upon the activity of the enzyme solution), remove i ml. of the reaction mixture, cool and add it to one of the test-tubes and note the colour obtained. At the beginning of the experiment the colour will be blue due to the starch alone. As the reaction proceeds, the colour gradually becomes violet, reddish, yellowish and finally colourless. The reason for this is that the starch is hydrolysed successively to
This is the end of the preview. Sign up
access the rest of the document.
This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.