Basic Biochemistry

SBC 229: Basic Biochemistry

Outline:

•Amino acids, the fundamentals of protein structure, isolation and purification of proteins, modification of proteins, and methods of determining protein conformation.

•Catalysis and enzyme kinetics

•Ion transport and other transport proteins

•Bioenergetics

•Glycolysis and the citric acid cycle

•ATP synthesis and membrane bound electron transfer in mitochondria

•Chloroplasts in plants and algae

•Molecular motors, such as muscles, which consume metabolic energy

AMINO ACIDS

•organic molecules - amine group, carboxylic acid group & a side-chain (R)

•4 key elements; C, N, H & O

•R varies in size

•Have salt-like behavior – zwitterion

AMINO ACIDS

•Classified by the properties of side-chains

•all but glycine can exist in either of two optical isomers, L or D; at least 1 chiral C

AMINO ACIDS Nutritionally

•Essential: Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, Valine, Histidine,

•Nonessential: Alanine, Aspartate, Glutamate*, Tyrosine*Arginine*, Cysteine*, Glutamine*, Glycine*, Proline*, Serine* Asparagine*

AMINO ACIDS

•Aliphatic – hydrophobic; core of a protein

•Acidic amino acids - highly polar, negatively charged

•Basic amino acids - positively charged

•Neutral polar amino acids - not charged, R have polar groups which can form H bonds; hydrophillic.

•Sulphur containing amino acids - a sulphur atom, hydrophobic

•Aromatic amino acids - an aromatic ring, highly hydrophobic

•Hydroxylic amino acids - hydroxyl group

•Amidic amino acids - an amide group

The primary structure

•-NH2 group at the left-hand end; -COOH group at the right-hand end.

The secondary structure

•Held together by hydrogen bonds between one of the lone pairs on an oxygen atom and the hydrogen attached to a nitrogen atom:

The secondary structure- the alpha helix

•The pp chain is coiled as a spring

•the carbonyl O of residue “i” forms a H bond with the amide of residue “i+4”

The secondary structure- the alpha helix

The secondary structure - Beta-pleated sheets

•Protein is arranged in a sheet.

•Rs would be above and below the plan of the sheet. H bonds between the CO and the NH groups

The tertiary structure

•A description of the folding of a protein to its final 3-dimensional shape 

Quaternary protein structure

•Regular association of two or more pp chains to form a complex

•May be composed of two or more identical polypeptides, or different polypeptides