However, scientists know through various research techniques that enzymes occur in a number of shapes and sizes. Although enzymes of different plants and animals have different protein structures, they function in similar ways. The structure of any particular enzyme enables it to cause chemical reactions in other molecules. Scientists sometimes change the structure of enzyme molecules to study how altered enzymes function or to make enzymes carry out different chemical reactions. An enzyme's structure can easily be destroyed by heat, acids, or alkalis.
Many deadly poisons act by damaging important enzymes.
Hereditary diseases may occur in people born without certain enzymes. In many cases, tests can detect these enzyme deficiencies. Physicians can sometimes treat them with diet and drugs to prevent deformities, mental retardation, and even death. Although most enzymes are proteins, some must be attached to certain nonprotein molecules in order to function. Many of these nonprotein molecules are metals, such as copper, iron, or magnesium.