Demonstrate how pH affects the activity of the enzymes invertase and amylase. Enzyme activity is measured using reduction of dintirosalicylic acid, which may be assessed visually or by spectrophotometer. The pH affects the activity of enzymes in two ways: by affecting the charges on groups in the enzyme’s three-dimensional active site and by altering the charges which hold the enzyme molecule together. Altering the charges in the active site can greatly change enzyme activity, but these changes are usually reversible. When an enzyme molecule is denatured by pH changes, the effects are usually not reversible and the enzyme becomes permanently inactive. Required, but not included: beakers, test tubes, and graduated cylinders; a hot plate or water bath,spectrophotometer or colorimeter (optional; absorption 540 nm). Includes prepaid reply card for invertase and amylase enzymes, which ship separately upon request within the continental United States. Allow 90-120 minutes lab time. Designed for 24 advanced biology or biochemistry students working in groups of four. Sh. wt. 2lbs, DIM 9” x 6” x 5”