Download A PRESENTATION ON AMINO ACIDS AND PROTEINS

A PRESENTATION ON
AMINO ACIDS AND PROTEINS
PRESENTED BY
SOMESH SHARMA
140920105012
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 a, b, g, etc. amino acids according
the carbon that bears the nitrogen.
The basic structure of amino acids differ only in the
structure of the or the side chain (R-group).
L-isomer
L-isomer is normally found in proteins.
Nonionic and zwitterion forms of amino acids
A zwitterion form of amino acid molecule contain both
positevly & negatively charge
Zwitterion = in German for „hybrid ion“
Week acid
Week base
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
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.
Essential Amino Acids in Humans
•
•
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
Non-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
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.
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