BSC 1010 Chapter Notes - Chapter 3: Post-Translational Modification, Amphiphile, Protein Structure
Document Summary
Enzymes serve as catalysts, increasing the rates of chemical reactions. Regulatory proteins- control and coordinate cell function. Transport proteins- move substances into and out of cells. Receptor proteins- enable cells to respond to chemical stimuli from the environment. Only 20 kinds of amino acids are used in protein synthesis: additional types can result from posttranslational modification. No two different proteins have the same amino acid sequence. Amino acids have the same basic structure: coo- and nh3+ groups are ionized at cellular ph, differences in properties arise from differences in the r group. R groups (side chains) are nonpolar: generally lack o and n. Cannot form electrostatic bonds or interact with water. Can be found within protein cores and transmembrane domains: associate with each other through van der waals forces and hydrophobic interactions. Polar amino acids tend to be found on the surfaces of proteins: maximize interactions with water and other polar or charged molecules.