A PRESENTATION ON AMINO ACIDS AND PROTEINS PRESENTED BY SOMESH SHARMA Chemical Engineering Arham Veerayatan Institute of Engineering Technology and Research- Haripar (370460)

Fundamentals While their name implies that amino acids are compounds that contain an —NH2 group and a —CO2H group, these groups are actually present as —NH3+ and —CO2– respectively. They are classified as , , , etc. amino acids according the carbon that bears the nitrogen.

L-isomer is normally found in proteins. The basic structure of amino acids differ only in the structure of the or the side chain (R-group). L-isomer

Nonionic and zwitterion forms of amino acids Week acid Week base Zwitterion = in German for „hybrid ion“ A zwitterion form of amino acid molecule contain both positevly & negatively charge

ISOELECTRIC POINT The isoelectronic point or isoionic point is the pH at which the amino acid does not migrate in an electric field. This means it is the pH at which the amino acid is neutral

Peptides are formed by condensation of the -COOH group of one amino acid and the NH group of another amino acid. The acid forming the peptide bond is named first. Example: if a dipeptide is formed from alanine and glycine so that the COOH group of glycine reacts with the NH group of alanine, then the dipeptide is called glycylalanine. PEPTIDES

Required in diet Humans incapable of forming requisite carbon skeleton Arginine* Histidine* Isoleucine Leucine Valine Lysine Methionine Threonine Phenylalanine Tryptophan * Essential in children, not in adults Essential Amino Acids in Humans

Not required in diet Can be formed from a-keto acids by transamination and subsequent reactions Alanine Asparagine Aspartate Glutamate Glutamine Glycine Proline Serine Cysteine (from Met*) Tyrosine (from Phe*) * Essential amino acids Non-Essential Amino Acids in Humans

PROTEINS Proteins are polymers of α-Amino acid bonded by peptide linkage Proteins are the building blocks of life. Every cell in the human body contains protein.

CLASSIFICATION OF PROTEINS Proteins are classified in two types based on chemical composition & molecular shape

CHEMICAL COMPOSITION According to this system protiens are divided into two classes Simple proteins :- the simple protiens are those which are made of chains of amino acids units only, joined by amides linkages. Conjugated proteins :- these molecules are made of a simple proteins united covalently or non covalently with non-protein factor.

MOLECULAR SHAPE The shape –classification divides proteins into two types depending on their molecular shape Fibrous proteins :- in this proteins the polypeptide chains coil about one another and are held together by strong inter-chain hydrogen bond. Globular proteins :- the molecules are globular or roughly spherical in shape. They are made of polypeptide chains coiled back and on themselves so as to make compact spheroid molecules.

STRUCTURE OF PROTEINS Proteins have a 3-dimensinal structure. It has a four different levels. Primary Secondary Tertiary Quaternary structures

Primary structure :- it refer to the sequence of amino acids sequence of amino acids in the proteins chains is essentially random. Secondary structure :- it refers to the shape in which long amino acid chain exist. many proteins consist of amino acid chain coiled into spiral shape. Tertiary structure :- the final 3-dimensional shape that result from twisting, bending,folding of protein helix. Quaternary structure :- complex protein are often formed from two or more amino acids chains rather than a single amino acid chain. It refers to the way in which these amino acids chains of a complex proteins are associated with each other.

THANK YOU