What are the functions of each type of protein?

There are 8 protein groups, categorized by their functions: 

1. Structural proteins such as collagen and keratin form the components of connective tissues, bones, tendons, and more. 
2. Enzymes such as lipase and DNA polymerase, are proteins that act as biological catalysts to speed up metabolic reactions. 
3. Hormones are proteins that regulate physiological processes such as growth and reproduction. Cortisol, growth hormone, thyroid hormone, and progesterone are just some of many hormones in the body.  
4. Motor proteins such as myosin, actin, and kinesin play a role in muscle contraction and movement. 
5. Transport proteins are involved in transporting molecules. Channel proteins transport molecules across the cell membrane while hemoglobin and serum albumin transport molecules through blood. 
6. Storage proteins such as ferritin and ovalbumin act as storage reserves of amino acids and metal ions in cells. 
7. Respiratory pigments are water-soluble proteins such as hemoglobin, which transfers blood to all tissues and organs, and myoglobin, which provide oxygen to working muscles. 
8. Toxins such as diphtheria toxin are proteins produced by bacteria to create cytotoxicity.