Detection of catalysis by taste

• Published in: Journal of chemical education Vol. 75; no. 3; p. 315
• Main Author: Richman, Robert M
• Format: Journal Article
• Language: English
• Published: Easton Division of Chemical Education 01-03-1998; American Chemical Society
• Subjects: Catalysis; Catalysts; Chemical Reactions; Chemistry; Concept Formation; Diagnostic systems; Diagnostic tests; Enzymes; Experiments; Foods Instruction; Higher Education; Human performance; Hydrogen peroxide; Laboratory Procedures; Long Term Memory; Organic Chemistry; Problem Solving; Science Curriculum; Science Education; Undergraduate Study; New York; United States > US; Demonstrations; Tested Demonstrations; Catalysis; High School / Introductory Chemistry
• ISSN: 0021-9584; 1938-1328
• DOI: 10.1021/ed075p315

A classroom demonstration is outlined to illustrate by taste the large effect that a small quantity of catalyst can have. The enzyme lactase, obtained from the over-the-counter product Lactaid, catalyzes the hydrolysis of the disaccharide lactose into D-glucose and D-galactose, its monosaccharide constituents. These products have a combined sweetening power of about 0.8 relative to sucrose. The sweetness can be easily discerned in milk that has been treated with Lactaid. It is readily apparent that the Lactaid itself is not the source of sweetness, since it is a rather tasteless substance that is diluted in milk by a factor of roughly 4000 to 1. It is estimated that each lactase molecule hydrolyzes 105 lactose molecules.