Tertiary : 3-dimensional shape, AA at opposite ends come close together.
Quaternary : a protein with more than one polypeptide chain and the arrangement relative to one another.
Purpose of Structure:
Proteins will vary in structure and shape and this is directly related to their function it was made for. The function of a protein will depend on its ability to recognize and bind to another molecule. (ex: enzyme binds to substrate, hormone binds to protein, antibody binds to foreign substance) In ‘hostile’ environments (temperature change, pH change, electrolyte concentration) the protein may unravel and loose it’s shape. This is called Denaturation (no longer functional).
Example: egg white (albumin) is clear – after heating, the proteins are denatured and turn white.
Enzymes
A protein, typically ending with the suffix “-ase”, that functions primarily as a biological catalyst in chemical reactions Normal body temp. and pressure(s) are too low to allow for rxns to occur fast enough to maintain life. However, raising the temperature can cause faster chemical rxns, but could also cause denaturation of proteins. The solution = enzymes. Enzymes speed up rxns by lowering the activation energy and properly orienting the molecules for better collision. The enzyme will not be permanently changed or used up in the reaction. Each enzyme has a binding site which binds to the substrates. Once binding has taken place, the substrates are brought close together and to the enzyme’s active site , which promotes the actual chemical reaction between the substrates. Some enzymes require cofactors or coenzymes . Management:
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