701. Enzyme Cytochemistry (EXP-701)

The concept that different enzymes are found in different tissues, cell types, and cell organelles is illustrated in this multipart exercise where students use contemporary techniques to localize specific enzymes in cells and tissues. Students are introduced to enzyme cytochemistry in an experiment on the germinating corn seed where they show that peroxidase is produced by the aleurone, a cell layer that surrounds the endosperm. They then characterize the subcellular distribution of peroxidase in giant onion epithelial cells and show that the enzyme resides in the cell wall. In the final experiment of the series, the subcellular distribution of lactate dehydrogenase in chicken erythrocytes is examined where students learn that this enzyme is confined to erythrocyte cytoplasm.