AP Bio Types of Proteins

Motor proteins

Motor proteins

Responsible for the active transport of proteins & vesicles along cytoskeleton filaments by converting chemical to mechanical energy. Myosin & kinesin are both two big examples of this.

Enzymes

Catalyze cellular reactions by breaking covalent bonds in carbohydrates. They bind to a substrate to do this. Maltase is an example of this, as it breaks down maltose into 2 glucose molecules.

Signaling Proteins

These bind to receptor proteins in order to mediate cell communication. They transmit information throughout the body by doing this, which is called signal transduction. These are also called ligands.

Special proteins

These are a unique category of proteins in which their characteristics don’t fit into any of the other categories. Some examples include GFP and botulin.

Gene Regulatory

Acts as an on-off switch and controls the function of genes by turning them off and on. One example is the lactose repressor, which controls the expression of lactose metabolic genes when there is a presence or absence of lactose.

Receptor

Bind to specific ligands and transmit the signals received by the signalling protein. They mediate interactions between cells and the extracellular environment. One example is acetylcholine receptors.

Storage

Stores nutrients such as ions and amino acids to a growing cell or organism. One example is casein, which is found in milk and provides amino acids to build muscles.

Transport

Found in the membrane and facilitates passive and active transport of substances across the membrane such as ions and sugars. These include channel and carrier proteins. Examples include hemoglobin (which transport O2) and aquaporins (which transport H2O)

Structural

Provides mechanical support to cells and tissues. One example is collagen, which gives support to skin and hair cells.