Sindh Biotechnologist Association has taken initiative for all young scientists, researchers, and students to have the platform to show their talent and interest in different activities. Topic: Peptides and Proteins Presented by Sana Aurangzeb For video Lecture: https://www.youtube.com/watch?v=KSadkkoUDCo

1. PRESENTER: SANA AURANGZEB
SINDH BIOTECHNOLOGIST ASSOCIATION
(SBA)

2. Topics
•Chemical properties of peptides and proteins
•Peptide bond
•Ionization behavior of peptides
•Size and composition of peptides and proteins
•Conjugated proteins
•Levels of structure in proteins

4. Chemical properties of Peptides and
Proteins
•Two amino acids are covalently joined through a
substituted amide linkage, termed a peptide bond.
•Such linkage is formed by the removal of elements of
water (dehydration) from the α-carboxyl group of one
amino acid and the α amino group of another.

5. Formation of Peptide bond by
condensation

6. •Three amino acids -------------Tripeptide
•Four amino acids---------------Tetrapeptide
•Five amino acids---------------Pentapeptide

7. •Many amino acids--------------Polypeptide
•Thousands of amino acids-----Proteins

8. •An amino acid unit in a peptide is often called a residue.
•In a peptide, the amino acid residue at the end with a free
α amino group is the amino-terminal or N-terminal
residue.
•The residue at the other end, which has a free carboxyl
group, is the carboxyl terminal (C-terminal) residue.

9. Peptides can be Distinguished by their
Iionization Behavior
•Peptides contain free α amino group and the one free α
carboxyl group at opposite end of the chain.
•The R groups of some amino acids can ionize, and in
peptide this contribute to the overall acid-base properties
of the molecule.

10. Biologically Active Peptides And Polypeptides
Occur in a vast range of Size and Composition

11. •Some proteins consists of single polypeptide chain.
•The protein in which two or more polypeptides are
associated noncovalently is known as multisubunits
proteins.
•If at least two polypeptide chains are identical the protein
is said to be oligomeric.
•The identical units consists of one or more polypeptide
chain are referred to as protomers.

12. Some Proteins contains Chemical Groups
Other thanAmino Acids

13. Levels of structures in proteins

14. Summary
•Amino Acids can be joined through peptide bonds to
form peptides and proteins.
•Some proteins are composed of several noncovalently
associated polypeptides chains, called subunits.
•On hydrolysis simple protein yield only amino acids.
•The sequence of amino acids in a protein is characteristic
of that protein and is called its primary structure. This is
one of four generally recognized levels of protein
structure.

15. Thank You