This stepwise degradation eventually yields the final products of carbon dioxide and water. The process prevents ethanol from building up to toxic levels in the body. In the first enzymatic reaction, methanol is broken down into formaldehyde . If you've ever dissected a frog in biology class, you may have witnessed one of the many uses of this chemical. Formaldehyde reacts with the amino acids in proteins.
Proteins are chains of amino acids that fold to form very unique structures.
The way these chains fold gives proteins the proper shape and the flexibility to interact with other molecules. Formaldehyde diffuses into tissues and cells where it forms crosslinks between different amino acids. This property makes formaldehyde useful for a number of chemical processes that fix things in a particular state. Formaldehyde doesn't stick around long in your body because it is so rapidly metabolized to formic acid by the second enzyme in this metabolic pathway. Formic acid is also extremely toxic to humans.