Part 4

Methionine, Serine, Threonine, Cysteine, Tyrosine, Asparagine, and Glutamine. Have polar, uncharged R-groups that are HYDROPHILIC, increasing the solubility of the amino acid in water. Usually found on protein surfaces.

Aspartic Acid, Glutamic Acid R-group contains carboxyl groups. They have net negative charge at physiological pH and exist in salt form in the body. Play important role in substrate-binding sites of enzymes. Have three distinct pKa’s

Arginine, Lysine, Histidine Amino acids whose R-group contains an amino group and carry a net positive charge at physiological pH.

If pH < pI, think positive charge. If pH > pI think negative charge.

Link amino acid subunits between the carboxyl group of one amino acid and the amino group of another. Formed via condensation reaction (water is lost).

Refers to sequence of amino acids listed from N- to C- terminus, linked by COVALENT bonds btw neighboring chains.

Local structure of neighboring amino acids, governed mostly by HYDROGEN bond interactions. Most common types are alpha-helix and beta-pleated sheet.

Rod-like structure in which the peptide chain coils clockwise about a central axis. e.g. keratin

Three-dimensional shape of the protein

Arrangement of polypeptide units

Have prosthetic groups.

Loss of three-dimensional structure.

Aldehydes and ketons with many hydroxyl groups

Simplest units and are classified by the number of carbons.

Based on stereochemistry of glyceraldehude. If Lowest -OH is on the LEFT, the molecule is L. If the -OH is on the RIGHT, its D.

Differ in configuration at only one carbon.

Fructose

Glucose, Galactose, and Mannose

Six-membered rings

five-membered rings

hemiacetal + alcohol –> acetal

Process of measuring the energy differences between the possible states of a molecular system by determining the frequencies of electromagnetic radiation absorbed by the molecules.

Measures molecular vibrations, which include bond stretching, bending, and rotation. Best used for identification of functional groups. Alcohols are BROAD peaks Acids are BROADEST peaks Ketones and Amines are SHARP peaks.

One of the most widely used spectroscopic tools in organic chemistry. NMR is based on the fact that certain nuclei have magnetic moments that are normally oriented at random. Most commonly used to study H nuclei (protons) and 13C nuclei, but any atom possessing a nuclear spin can be studied.