BIOC 2300 Study Guide - Final Guide: Asymmetric Carbon, Alpha And Beta Carbon, Conjugate Acid
19 Apr 2014
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Document Summary
Proteins are distinguished by the number/composition/sequence of amino acid residues amino acid polymers <50 amino acids = peptides. There are 20 standard amino acids: 19 have the same general structure central alpha carbon, an amino group, a carboxylate group, hydrogen atom, an r group (exception is proline) R group gives the amino acid its unique properties. Polar amino acids have functional groups that can easily interact with water through hydrogen bonding: contain a hydroxyl group. Tyrosine: or contain an amide group. Acidic amino acids have side chains with a carboxylate group that ionizes at physiological ph: aspartate, glutamate. Basic amino acids have a positive charge at physiological ph: at physiological ph lysine is its conjugate acid (-nh3+), arginine is permanently pronated, and histidine is a weak base (only partly ionized) Some proteins have amino acids that can be modified after synthesis: serine, threonine, tyrosine can be phosphorylated.
