Final answer:
Horseradish peroxidase and alkaline phosphatase are enzymes used in ELISA tests, which are vital in clinical diagnostics to detect the presence of specific antigens or antibodies.
Step-by-step explanation:
Horseradish peroxidase and alkaline phosphatase are enzymes commonly used in Enzyme Linked Immunosorbent Assay (ELISA) tests. These enzymes act as markers that are conjugated to antibodies used in various ELISA protocols. When a substrate specific to these enzymes is added, a color change occurs, indicating the presence or absence of antigens. This test is crucial in various areas of clinical diagnostics and research, such as detecting specific proteins, antibodies, or hormones.
Types of ELISA tests using these enzymes include:
- Direct ELISA - to quantify an antigen with a single antibody that is enzyme-linked.
- Indirect ELISA - to detect antibodies in a sample using a secondary enzyme-conjugated antibody.
- Sandwich ELISA - involves capturing an antigen with a primary antibody and then detecting it with a secondary enzyme-conjugated antibody.
Thus, the answer to the student's question is b. ELISA.