Can substitution of one amino acid in the chain affect the function of the protein?

Can substitution of one amino acid in the chain affect the function of the protein? Is the genetic information in the liver cell and in the nerve cell of the same organism the same?

Proteins are made up of amino acids. There are a total of 20 amino acids that are used in protein synthesis. If one amino acid is changed in one protein, then it most likely will not be able to perform functions or will perform other functions. It will either be a completely different protein, or it will not work.
DNA is the same in all cells of the body. The only exceptions are sex cells. They have only half of the human chromosome set. Therefore, liver cells and nerve cells have the same genetic information.