General Biochemistry (BCHEM 154) - Amino Acids, Proteins, Enzymes, and Nucleic Acids
Amino acids are organic compounds that serve as the building blocks for proteins. Each amino acid has a basic structure that includes a central carbon atom, an amino group (-NH_2), a carboxyl group (-COOH), a hydrogen atom, and a variable side chain or R group that determines the specific properties of each amino acid.
Functions of Amino Acids:
- They play a critical role in various biological processes, including enzyme catalysis, immune response, and cell signaling.
- Amino acids are classified into three categories:
- Essential amino acids: Cannot be synthesized by the body and must be obtained from the diet (e.g., lysine, methionine).
- Non-essential amino acids: Can be synthesized by the body (e.g., alanine, aspartic acid).
- Conditional amino acids: Typically non-essential but may become essential in times of illness or stress (e.g., glutamine).
Protein Structure:
- Proteins are formed through the polymerization of amino acids through peptide bonds, creating polypeptides.
- The structure of proteins can be divided into four levels:
- Primary structure: The linear sequence of amino acids in a polypeptide chain.
- Secondary structure: Local folding patterns such as alpha-helices and beta-sheets stabilized by hydrogen bonds.
- Tertiary structure: The overall three-dimensional shape of a polypeptide, maintained by various interactions (e.g., hydrophobic interactions, ionic bonds).
- Quaternary structure: The assembly of multiple polypeptide chains into a functional protein (e.g., hemoglobin, which consists of four polypeptide subunits).
Importance of Proteins:
- They are essential for growth, repair, and maintenance of tissues.
- Proteins function as enzymes, hormones, structural components, and transport molecules, critical for biological processes.
- The shape and structure of proteins are crucial for their specific functions, making them finely tuned to fulfill diverse roles in the body.