The isolation of enzymes from infected tissue can also provide the basis of a biochemical diagnosis of an infectious disease. For example, <answer>humans can make neither RNA replicases nor reverse transcriptase</answer>, and the presence of these enzymes are characteristic of specific types of viral infections. The ability of the viral protein hemagglutinin to bind red blood cells together into a detectable matrix may also be characterized as a biochemical test for viral infection, although strictly speaking hemagglutinin is not an enzyme and has no metabolic function.
Why are the presence of certain enymzes a tell tale sign of a virus?
humans can make neither RNA replicases nor reverse transcriptase