Protein Structure And Function Notes.

All amino acids except glycine are chiral molecules meaning they cannot be superimposed on each other. Glycine does not have a chiral center hence it is known as achiral. At neutral pH, amino acids exist as zwitterions. This means they are ionized and have a positive and negative charge. The pH determines the ionization state of the alpha carboxyl and amino groups. In acidic solutions the carboxyl group is not ionized whereas the amino group is ionized. Hence the amino acid has a +1 charge. In basic solutions the carboxyl group is ionized and the amino group is not ionized. Hence the amino acid has a negative charge. The carboxylic acid condenses with the amino group releasing waterThe amino acid sequence is called the primary structure, 1°. The primary structure is the first of four protein structure levels. A native protein will have up to 4 different levels of structure:Primary, 1Secondary, 2Tertiary, 3Quaternary, 4Many but not all proteins will have a quaternary structure but all proteins will have a primary, secondary and tertiary structure. Amino acids are assembled together by peptide bonds. The