Proteins and amino acids

Protein Facts Proteins: Polymers of Amino Acids Proteins are polymers of amino acids. They are molecules with diverse structures and functions. Each different type of protein has a characteristic amino acid composition and order. Proteins range in size from a few amino acids to thousands of them. Folding is crucial to the function of a protein and is influenced largely by the sequence of amino acids.

Proteins are polymers Proteins are polymers of amino acids. They are molecules with diverse structures and functions. Polymers are made up of units called monomers The monomers in proteins are the 20 amino acids

Proteins: Polymers of Amino Acids Each different type of protein has a characteristic amino acid composition and order. Proteins range in size from a few amino acids to thousands of them. Folding is crucial to the function of a protein and is influenced largely by the sequence of amino acids.

Polar side chains

Non Polar Hydrophobic side chains

Electrical charged hydrophilic

Functions of proteins Hormones – Growth hormone Receptors – to Receive information so that cell can communicate with other cells Neurotransmitters – messenger molecules – to send information between neurons Cytoskeleton – actin, myosin, and collagen – the structure of connective tissue and muscles Antibodies – Immunoglobulins to fight disease

Function of Proteins - continued Enzymes – Biological catalysts Transport of small molecules – Albumin and haptoglobin Transport of oxygen – hemoglobin and myoglobin Membrane proteins – to assist in support Channels in membranes – to allow the passage of molecules or ions Electron carriers in electron transport in the production of ATP

Functions( continued)i Clotting proteins Immune proteins to fight infectious agents Histones – DNA binding proteins Toxins to repel or kill other organisms Bacteriocins – molecules produced by bacteria against bacteria

Biochemical Reactions Polymerization reaction- condensation and dehydration synthesis – involves the loss of water between two amino acids and the formation of a peptide bond ( OH is lost from the carboxyl group and H is lost from the hydroxyl) requires energy Hydrolysis – the addition of water causes the peptide bond to break and the amino acids to separate( releases energy)

Polymerization

Hydrolysis

Four levels of Protein Structure There are four levels of protein structure: primary, secondary, tertiary, and quaternary. The precise sequence of amino acids is called its primary structure. The peptide backbone consists of repeating units of atoms: N—C—C—N—C—C. Enormous numbers of different proteins are possible.