The function of a protein is determined by its what?

The function of a protein is determined by its 3D structure because the specific shape of a protein allows it to interact with other molecules in a precisely defined manner. Proteins are made up of amino acids that fold into unique three-dimensional shapes, which are critical for their function. For instance, enzymes, which are a type of protein, have active sites that are specifically shaped to bind to their substrates, facilitating biochemical reactions.

The three-dimensional structure of a protein is maintained by various interactions, such as hydrogen bonds, ionic bonds, hydrophobic interactions, and van der Waals forces. If the structure of the protein is altered, even slightly, it can lead to a loss of function or aberrant activity, which is seen in diseases caused by misfolded proteins.

Other factors like mass, solubility, and color may provide information about the protein or its interactions but do not directly determine its functional capacity. For example, while solubility can affect a protein's ability to function in certain environments, it is the overall 3D conformation that dictates how and whether a protein can carry out its specific role within biological systems.