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Chemistry LibreTexts

13: Amino Acids and Proteins

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  • Amino acids are molecules containing an amine group(NH2), a carboxylic acid group(R-C=O-OH) and a side-chain( usually denoted as R) that varies between different amino acids. They are particularly important in biochemistry, where the term usually refers to alpha-amino acids. Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form in a biologically functional way.

    • 13.1: Amino Acids
      An amino acid is a compound that contains both an amine group and a carboxyl group in the same molecule. While any number of amino acids can possibly be imagined, biochemists generally reserve the term for a group of 20 amino acids which are formed and used by living organisms.
    • 13.2: Peptides
      A peptide is a combination of amino acids in which the amine group of one amino acid has undergone a reaction with the carboxyl group of another amino acid. The reaction is a condensation reaction, forming an amide group.
    • 13.3: Protein Structure
      A polypeptide is a sequence of amino acids between ten and one hundred in length. A protein is a peptide that is greater than one hundred amino acids in length. The three-dimensional structure of a protein is very critical to its function. This structure can be broken down into four levels.
    • 13.4: Amino Acids and Proteins (Exercises)
      These are homework exercises to accompany Chapter 13 of the University of Kentucky's LibreText for CHE 103 - Chemistry for Allied Health. Solutions are available below the questions.