CHEM 343 Lecture Notes - Isoelectric Point, Fischer Projection, Amine
Document Summary
Peptides and proteins are polymers of amino acids linked together by amide bonds. The monomeric units are called amino acids residues. Oligopeptide contains three to ten amino acid residues. Proteins are naturally occurring polypeptides that are made up of 40 to 4000 amino acid residues. Proteins and polypeptides serve many functions in biological systems. There are 20 most common naturally occurring amino acids. The amino acids differ only in the substituent (r) attached to the -carbon. The wide variation in these side chains is what gives proteins their great structural diversity and, as a consequence, their great functional diversity. Ten of the amino acids are essential amino acids. We humans must obtain these ten amino acids from our diets because we either cannot synthesize them at all or cannot synthesize them in adequate amounts. The d and l isomers of monosaccharides and amino acids are defined the same way. Almost all sugars found in nature are d-sugars.
