Proteins serve many functions within cells. They aid in cellular transport within the cell. They assist with the transport of substances across the cell membrane. They form enzymes that are involved in many cellular processes, and so on.

However, proteins do not function properly unless they are immersed in water. This is because water

determines the amino acid sequences found in proteins.
serves as a catalyst for metabolic reactions involving proteins.
helps to maintain the structure, flexibility, and motion of proteins.
reacts with proteins to form new complexes.