- Enzymes
- Help “catalyze” chemical reactions
- Structural Proteins
- Give support, strength, flexibility
- Examples: collagen, elastin, keratin
- Storage Proteins
- Storage of amino acids, for building proteins later or energy
- Examples: egg albumin (ovalbumin), Casein (in milk)
- Transport Proteins
- Examples: Hemoglobin (O2), H+ pump
- Signaling Proteins
- Hormonal Proteins and receptor proteins
- Example: Insulin and Insulin receptor
- Motor Proteins
- Actin and myosin perform muscle contraction
- Immune Defense Proteins
- Antibodies help fight infection