Proteins are made from long chains of smaller molecules called amino acids. These long chains are folded into particular shapes. This is important in relation to how antibodies and enzymes work.
Enzymes are biological catalysts. There are optimum temperatures and pH values at which their activity is greatest. Enzymes are also proteins. If the shape of an enzyme changes, it may no longer work (it is said to have been 'denatured'). maybe right?